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Diffstat (limited to 'doc')
| -rw-r--r-- | doc/ChangeLog | 76 | ||||
| -rw-r--r-- | doc/awkcard.in | 13 | ||||
| -rw-r--r-- | doc/gawk.1 | 11 | ||||
| -rw-r--r-- | doc/gawk.info | 3205 | ||||
| -rw-r--r-- | doc/gawk.texi | 2020 | ||||
| -rw-r--r-- | doc/gawktexi.in | 2012 | ||||
| -rw-r--r-- | doc/texinfo.tex | 49 |
7 files changed, 4581 insertions, 2805 deletions
diff --git a/doc/ChangeLog b/doc/ChangeLog index 52574058..d4f6881b 100644 --- a/doc/ChangeLog +++ b/doc/ChangeLog @@ -1,3 +1,79 @@ +2014-04-08 Arnold D. Robbins <arnold@skeeve.com> + + * 4.1.1: Release tar ball made. + +2014-04-08 Arnold D. Robbins <arnold@skeeve.com> + + * texinfo.tex: Update to latest. + * awkcard.in: Update copyright, patchlevel in download. + * gawktexi.in: Update patchlevel, update month, spell check. + +2014-03-30 Arnold D. Robbins <arnold@skeeve.com> + + * gawktexi.in: Cleanups to docbook, finish math stuff. + +2014-03-28 Arnold D. Robbins <arnold@skeeve.com> + + * gawktexi.in: Minor cleanups to the indexing. + + Unrelated: + + * gawktexi.in: Merge in changes needed for creating valid + DocBook XML. Works with post-5.2 Texinfo and dblatex! + +2014-03-27 Arnold D. Robbins <arnold@skeeve.com> + + * gawktexi.in: Finish the massive indexing improvements such that + functions are indexed the way I want in TeX and the way Eli + wants in Info. + + Unrelated: + + * gawktexi.in: Add a note in extension chapter that lookup of + PROCINFO can fail. + +2014-03-27 Eli Zaretskii <eliz@gnu.org> + + * gawktexi.in: First round of massive indexing improvements. + +2014-03-27 Antonio Giovanni Colombo <azc100@gmail.com> + + * gawktexi.in: Redo all the examples using BBS-list to a different + file that doesn't use out-of-date concepts. + +2014-03-10 Arnold D. Robbins <arnold@skeeve.com> + + * gawktexi.in: Finish indexing improvements. (For now, anyway.) + + Unrelated: + + * gawk.1: Document the quote flag! (Better late than never.) + * awkcard.in: Update documentation of quote flag. + +2014-03-08 Arnold D. Robbins <arnold@skeeve.com> + + * gawktexi.in: Minor edits to the discussion of the memory allocation + functions. + +2014-03-08 Andrew J. Schorr <aschorr@telemetry-investments.com> + + * gawktexi.in: Document new extension API functions api_malloc, + api_calloc, api_realloc, and api_free. + +2014-03-07 Arnold D. Robbins <arnold@skeeve.com> + + * gawktexi.in: Indexing improvements. + +2014-03-02 John E. Malmberg <wb8tyw@qsl.net> + + * gawktexi.in: Remove paragraph about obsolete VMS + compilers. Update reference about building PCSI kit. + +2014-02-27 Arnold D. Robbins <arnold@skeeve.com> + + * gawktexi.in: Lots of small fixes throughout, update of + profiling output. Finished fixes needed before a release. + 2014-02-20 Arnold D. Robbins <arnold@skeeve.com> * gawktexi.in: Add a quote to the alarm clock program. diff --git a/doc/awkcard.in b/doc/awkcard.in index 610032b7..ca28f0a7 100644 --- a/doc/awkcard.in +++ b/doc/awkcard.in @@ -1,7 +1,7 @@ .\" AWK Reference Card --- Arnold Robbins, arnold@skeeve.com .\" .\" Copyright (C) 1996, 1997, 1998, 1999, 2000, 2001, 2002, -.\" 2003, 2004, 2005, 2007, 2009, 2010, 2011, 2012, 2013 +.\" 2003, 2004, 2005, 2007, 2009, 2010, 2011, 2012, 2013, 2014 .\" Free Software Foundation, Inc. .\" .\" Permission is granted to make and distribute verbatim copies of @@ -100,7 +100,7 @@ Brian Kernighan and Michael Brennan who reviewed it. \*(CD .SL .nf -\*(FRCopyright \(co 1996\(en2005, 2007, 2009\(en2013 +\*(FRCopyright \(co 1996\(en2005, 2007, 2009\(en2014 Free Software Foundation, Inc. .nf .BT @@ -1493,7 +1493,8 @@ Only has an effect when the field width is wider than the value to be printed. T} \*(CB\*(FC'\*(FR T{ -Use the locale's thousands separator for \*(FC%d\fP, \*(FC%i\fP, and \*(FC%u\fP.\*(CD +Use the locale's thousands separator and decimal +point characters.\*(CD T} \*(FIwidth\fP T{ Pad the field to this width. The field is normally @@ -1938,7 +1939,7 @@ to use the current domain.\*(CB .ES .nf \*(CDHost: \*(FCftp.gnu.org\*(FR -File: \*(FC/gnu/gawk/gawk-4.1.0.tar.gz\fP +File: \*(FC/gnu/gawk/gawk-4.1.1.tar.gz\fP .in +.2i .fi GNU \*(AK (\*(GK). There may be a later version. @@ -1968,8 +1969,8 @@ maintains it.\*(CX .\" --- Copying Permissions .ES .fi -\*(CDCopyright \(co 1996, 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005, -2007, 2009, 2010, 2011, 2012, 2013 Free Software Foundation, Inc. +\*(CDCopyright \(co 1996\(en2005, +2007, 2009\(en2014 Free Software Foundation, Inc. .sp .5 Permission is granted to make and distribute verbatim copies of this reference card provided the copyright notice and this permission notice @@ -13,7 +13,7 @@ . if \w'\(rq' .ds rq "\(rq . \} .\} -.TH GAWK 1 "Jan 28 2014" "Free Software Foundation" "Utility Commands" +.TH GAWK 1 "Mar 08 2014" "Free Software Foundation" "Utility Commands" .SH NAME gawk \- pattern scanning and processing language .SH SYNOPSIS @@ -2454,6 +2454,15 @@ This applies only to the numeric output formats. This flag only has an effect when the field width is wider than the value to be printed. .TP +.B ' +A single quote character instructs +.I gawk +to insert the locale's thousands-separator character +into decimal numbers, and to also use the locale's +decimal point character with floating point formats. +This requires correct locale support in the C library +and in the definition of the current locale. +.TP .I width The field should be padded to this width. The field is normally padded with spaces. With the diff --git a/doc/gawk.info b/doc/gawk.info index 5deb6482..aad73f7a 100644 --- a/doc/gawk.info +++ b/doc/gawk.info @@ -9,13 +9,12 @@ START-INFO-DIR-ENTRY * awk: (gawk)Invoking gawk. Text scanning and processing. END-INFO-DIR-ENTRY - Copyright (C) 1989, 1991, 1992, 1993, 1996, 1997, 1998, 1999, 2000, -2001, 2002, 2003, 2004, 2005, 2007, 2009, 2010, 2011, 2012, 2013, 2014 + Copyright (C) 1989, 1991, 1992, 1993, 1996-2005, 2007, 2009-2014 Free Software Foundation, Inc. This is Edition 4.1 of `GAWK: Effective AWK Programming: A User's -Guide for GNU Awk', for the 4.1.0 (or later) version of the GNU +Guide for GNU Awk', for the 4.1.1 (or later) version of the GNU implementation of AWK. Permission is granted to copy, distribute and/or modify this document @@ -41,13 +40,12 @@ General Introduction This file documents `awk', a program that you can use to select particular records in a file and perform operations upon them. - Copyright (C) 1989, 1991, 1992, 1993, 1996, 1997, 1998, 1999, 2000, -2001, 2002, 2003, 2004, 2005, 2007, 2009, 2010, 2011, 2012, 2013, 2014 + Copyright (C) 1989, 1991, 1992, 1993, 1996-2005, 2007, 2009-2014 Free Software Foundation, Inc. This is Edition 4.1 of `GAWK: Effective AWK Programming: A User's -Guide for GNU Awk', for the 4.1.0 (or later) version of the GNU +Guide for GNU Awk', for the 4.1.1 (or later) version of the GNU implementation of AWK. Permission is granted to copy, distribute and/or modify this document @@ -522,6 +520,7 @@ texts being (a) (see below), and with the Back-Cover Texts being (b) * Extension API Functions Introduction:: Introduction to the API functions. * General Data Types:: The data types. * Requesting Values:: How to get a value. +* Memory Allocation Functions:: Functions for allocating memory. * Constructor Functions:: Functions for creating values. * Registration Functions:: Functions to register things with `gawk'. @@ -584,7 +583,8 @@ texts being (a) (see below), and with the Back-Cover Texts being (b) version of `awk'. * POSIX/GNU:: The extensions in `gawk' not in POSIX `awk'. -* Feature History:: The history of the features in `gawk'. +* Feature History:: The history of the features in + `gawk'. * Common Extensions:: Common Extensions Summary. * Ranges and Locales:: How locales used to affect regexp ranges. @@ -1766,30 +1766,30 @@ File: gawk.info, Node: Sample Data Files, Next: Very Simple, Prev: Running ga =============================== Many of the examples in this Info file take their input from two sample -data files. The first, `BBS-list', represents a list of computer -bulletin board systems together with information about those systems. +data files. The first, `mail-list', represents a list of peoples' names +together with their email addresses and information about those people. The second data file, called `inventory-shipped', contains information about monthly shipments. In both files, each line is considered to be one "record". - In the data file `BBS-list', each record contains the name of a -computer bulletin board, its phone number, the board's baud rate(s), -and a code for the number of hours it is operational. An `A' in the -last column means the board operates 24 hours a day. A `B' in the last -column means the board only operates on evening and weekend hours. A -`C' means the board operates only on weekends: - - aardvark 555-5553 1200/300 B - alpo-net 555-3412 2400/1200/300 A - barfly 555-7685 1200/300 A - bites 555-1675 2400/1200/300 A - camelot 555-0542 300 C - core 555-2912 1200/300 C - fooey 555-1234 2400/1200/300 B - foot 555-6699 1200/300 B - macfoo 555-6480 1200/300 A - sdace 555-3430 2400/1200/300 A - sabafoo 555-2127 1200/300 C + In the data file `mail-list', each record contains the name of a +person, his/her phone number, his/her email-address, and a code for +their relationship with the author of the list. An `A' in the last +column means that the person is an acquaintance. An `F' in the last +column means that the person is a friend. An `R' means that the person +is a relative: + + Amelia 555-5553 amelia.zodiacusque@gmail.com F + Anthony 555-3412 anthony.asserturo@hotmail.com A + Becky 555-7685 becky.algebrarum@gmail.com A + Bill 555-1675 bill.drowning@hotmail.com A + Broderick 555-0542 broderick.aliquotiens@yahoo.com R + Camilla 555-2912 camilla.infusarum@skynet.be R + Fabius 555-1234 fabius.undevicesimus@ucb.edu F + Julie 555-6699 julie.perscrutabor@skeeve.com F + Martin 555-6480 martin.codicibus@hotmail.com A + Samuel 555-3430 samuel.lanceolis@shu.edu A + Jean-Paul 555-2127 jeanpaul.campanorum@nyu.edu R The data file `inventory-shipped' represents information about shipments during the year. Each record contains the month, the number @@ -1826,32 +1826,32 @@ File: gawk.info, Node: Very Simple, Next: Two Rules, Prev: Sample Data Files, ======================== The following command runs a simple `awk' program that searches the -input file `BBS-list' for the character string `foo' (a grouping of +input file `mail-list' for the character string `li' (a grouping of characters is usually called a "string"; the term "string" is based on similar usage in English, such as "a string of pearls," or "a string of cars in a train"): - awk '/foo/ { print $0 }' BBS-list + awk '/li/ { print $0 }' mail-list -When lines containing `foo' are found, they are printed because +When lines containing `li' are found, they are printed because `print $0' means print the current line. (Just `print' by itself means the same thing, so we could have written that instead.) - You will notice that slashes (`/') surround the string `foo' in the -`awk' program. The slashes indicate that `foo' is the pattern to -search for. This type of pattern is called a "regular expression", -which is covered in more detail later (*note Regexp::). The pattern is -allowed to match parts of words. There are single quotes around the -`awk' program so that the shell won't interpret any of it as special -shell characters. + You will notice that slashes (`/') surround the string `li' in the +`awk' program. The slashes indicate that `li' is the pattern to search +for. This type of pattern is called a "regular expression", which is +covered in more detail later (*note Regexp::). The pattern is allowed +to match parts of words. There are single quotes around the `awk' +program so that the shell won't interpret any of it as special shell +characters. Here is what this program prints: - $ awk '/foo/ { print $0 }' BBS-list - -| fooey 555-1234 2400/1200/300 B - -| foot 555-6699 1200/300 B - -| macfoo 555-6480 1200/300 A - -| sabafoo 555-2127 1200/300 C + $ awk '/li/ { print $0 }' mail-list + -| Amelia 555-5553 amelia.zodiacusque@gmail.com F + -| Broderick 555-0542 broderick.aliquotiens@yahoo.com R + -| Julie 555-6699 julie.perscrutabor@skeeve.com F + -| Samuel 555-3430 samuel.lanceolis@shu.edu A In an `awk' rule, either the pattern or the action can be omitted, but not both. If the pattern is omitted, then the action is performed @@ -1860,7 +1860,7 @@ is to print all lines that match the pattern. Thus, we could leave out the action (the `print' statement and the curly braces) in the previous example and the result would be the same: -`awk' prints all lines matching the pattern `foo'. By comparison, +`awk' prints all lines matching the pattern `li'. By comparison, omitting the `print' statement but retaining the curly braces makes an empty action that does nothing (i.e., no lines are printed). @@ -1966,25 +1966,19 @@ the string `21'. If a line contains both strings, it is printed twice, once by each rule. This is what happens if we run this program on our two sample data -files, `BBS-list' and `inventory-shipped': +files, `mail-list' and `inventory-shipped': $ awk '/12/ { print $0 } - > /21/ { print $0 }' BBS-list inventory-shipped - -| aardvark 555-5553 1200/300 B - -| alpo-net 555-3412 2400/1200/300 A - -| barfly 555-7685 1200/300 A - -| bites 555-1675 2400/1200/300 A - -| core 555-2912 1200/300 C - -| fooey 555-1234 2400/1200/300 B - -| foot 555-6699 1200/300 B - -| macfoo 555-6480 1200/300 A - -| sdace 555-3430 2400/1200/300 A - -| sabafoo 555-2127 1200/300 C - -| sabafoo 555-2127 1200/300 C + > /21/ { print $0 }' mail-list inventory-shipped + -| Anthony 555-3412 anthony.asserturo@hotmail.com A + -| Camilla 555-2912 camilla.infusarum@skynet.be R + -| Fabius 555-1234 fabius.undevicesimus@ucb.edu F + -| Jean-Paul 555-2127 jeanpaul.campanorum@nyu.edu R + -| Jean-Paul 555-2127 jeanpaul.campanorum@nyu.edu R -| Jan 21 36 64 620 -| Apr 21 70 74 514 -Note how the line beginning with `sabafoo' in `BBS-list' was printed +Note how the line beginning with `Jean-Paul' in `mail-list' was printed twice, once for each rule. @@ -2060,7 +2054,7 @@ Most often, each line in an `awk' program is a separate statement or separate rule, like this: awk '/12/ { print $0 } - /21/ { print $0 }' BBS-list inventory-shipped + /21/ { print $0 }' mail-list inventory-shipped However, `gawk' ignores newlines after any of the following symbols and keywords: @@ -2480,7 +2474,7 @@ The following list describes options mandated by the POSIX standard: `--bignum' Force arbitrary precision arithmetic on numbers. This option has no effect if `gawk' is not compiled to use the GNU MPFR and MP - libraries (*note Arbitrary Precision Arithmetic::). + libraries (*note Gawk and MPFR::). `-n' `--non-decimal-data' @@ -2748,13 +2742,14 @@ on the command-line with the `-f' option. In most `awk' implementations, you must supply a precise path name for each program file, unless the file is in the current directory. But in `gawk', if the file name supplied to the `-f' or `-i' options does not contain a -`/', then `gawk' searches a list of directories (called the "search -path"), one by one, looking for a file with the specified name. +directory separator `/', then `gawk' searches a list of directories +(called the "search path"), one by one, looking for a file with the +specified name. The search path is a string consisting of directory names separated by -colons. `gawk' gets its search path from the `AWKPATH' environment +colons(1). `gawk' gets its search path from the `AWKPATH' environment variable. If that variable does not exist, `gawk' uses a default path, -`.:/usr/local/share/awk'.(1) +`.:/usr/local/share/awk'.(2) The search path feature is particularly useful for building libraries of useful `awk' functions. The library files can be placed in a @@ -2795,7 +2790,9 @@ found, and `gawk' no longer needs to use `AWKPATH'. ---------- Footnotes ---------- - (1) Your version of `gawk' may use a different directory; it will + (1) Semicolons on MS-Windows and MS-DOS. + + (2) Your version of `gawk' may use a different directory; it will depend upon how `gawk' was built and installed. The actual directory is the value of `$(datadir)' generated when `gawk' was configured. You probably don't need to worry about this, though. @@ -3105,14 +3102,14 @@ A regular expression can be used as a pattern by enclosing it in slashes. Then the regular expression is tested against the entire text of each record. (Normally, it only needs to match some part of the text in order to succeed.) For example, the following prints the -second field of each record that contains the string `foo' anywhere in +second field of each record that contains the string `li' anywhere in it: - $ awk '/foo/ { print $2 }' BBS-list - -| 555-1234 + $ awk '/li/ { print $2 }' mail-list + -| 555-5553 + -| 555-0542 -| 555-6699 - -| 555-6480 - -| 555-2127 + -| 555-3430 Regular expressions can also be used in matching expressions. These expressions allow you to specify the string to match against; it need @@ -3920,67 +3917,82 @@ processed, so that the very first record is read with the proper separator. To do this, use the special `BEGIN' pattern (*note BEGIN/END::). For example: - awk 'BEGIN { RS = "/" } - { print $0 }' BBS-list - -changes the value of `RS' to `"/"', before reading any input. This is -a string whose first character is a slash; as a result, records are -separated by slashes. Then the input file is read, and the second rule -in the `awk' program (the action with no pattern) prints each record. -Because each `print' statement adds a newline at the end of its output, -this `awk' program copies the input with each slash changed to a -newline. Here are the results of running the program on `BBS-list': - - $ awk 'BEGIN { RS = "/" } - > { print $0 }' BBS-list - -| aardvark 555-5553 1200 - -| 300 B - -| alpo-net 555-3412 2400 - -| 1200 - -| 300 A - -| barfly 555-7685 1200 - -| 300 A - -| bites 555-1675 2400 - -| 1200 - -| 300 A - -| camelot 555-0542 300 C - -| core 555-2912 1200 - -| 300 C - -| fooey 555-1234 2400 - -| 1200 - -| 300 B - -| foot 555-6699 1200 - -| 300 B - -| macfoo 555-6480 1200 - -| 300 A - -| sdace 555-3430 2400 - -| 1200 - -| 300 A - -| sabafoo 555-2127 1200 - -| 300 C + awk 'BEGIN { RS = "u" } + { print $0 }' mail-list + +changes the value of `RS' to `u', before reading any input. This is a +string whose first character is the letter "u;" as a result, records +are separated by the letter "u." Then the input file is read, and the +second rule in the `awk' program (the action with no pattern) prints +each record. Because each `print' statement adds a newline at the end +of its output, this `awk' program copies the input with each `u' +changed to a newline. Here are the results of running the program on +`mail-list': + + $ awk 'BEGIN { RS = "u" } + > { print $0 }' mail-list + -| Amelia 555-5553 amelia.zodiac + -| sq + -| e@gmail.com F + -| Anthony 555-3412 anthony.assert + -| ro@hotmail.com A + -| Becky 555-7685 becky.algebrar + -| m@gmail.com A + -| Bill 555-1675 bill.drowning@hotmail.com A + -| Broderick 555-0542 broderick.aliq + -| otiens@yahoo.com R + -| Camilla 555-2912 camilla.inf + -| sar + -| m@skynet.be R + -| Fabi + -| s 555-1234 fabi + -| s. + -| ndevicesim + -| s@ + -| cb.ed + -| F + -| J + -| lie 555-6699 j + -| lie.perscr + -| tabor@skeeve.com F + -| Martin 555-6480 martin.codicib + -| s@hotmail.com A + -| Sam + -| el 555-3430 sam + -| el.lanceolis@sh + -| .ed + -| A + -| Jean-Pa + -| l 555-2127 jeanpa + -| l.campanor + -| m@ny + -| .ed + -| R -| -Note that the entry for the `camelot' BBS is not split. In the -original data file (*note Sample Data Files::), the line looks like -this: +Note that the entry for the name `Bill' is not split. In the original +data file (*note Sample Data Files::), the line looks like this: - camelot 555-0542 300 C + Bill 555-1675 bill.drowning@hotmail.com A -It has one baud rate only, so there are no slashes in the record, -unlike the others which have two or more baud rates. In fact, this -record is treated as part of the record for the `core' BBS; the newline +It contains no `u' so there is no reason to split the record, unlike +the others which have one or more occurrences of the `u'. In fact, +this record is treated as part of the previous record; the newline separating them in the output is the original newline in the data file, not the one added by `awk' when it printed the record! Another way to change the record separator is on the command line, using the variable-assignment feature (*note Other Arguments::): - awk '{ print $0 }' RS="/" BBS-list + awk '{ print $0 }' RS="u" mail-list -This sets `RS' to `/' before processing `BBS-list'. +This sets `RS' to `u' before processing `mail-list'. - Using an unusual character such as `/' for the record separator -produces correct behavior in the vast majority of cases. + Using an alphabetic character such as `u' for the record separator +is highly likely to produce strange results. Using an unusual +character such as `/' is more likely to produce correct behavior in the +majority of cases, but there are no guarantees. The moral is: Know Your +Data. There is one unusual case, that occurs when `gawk' is being fully POSIX-compliant (*note Options::). Then, the following (extreme) @@ -4149,26 +4161,24 @@ get the empty string. (If used in a numeric operation, you get zero.) field, is a special case: it represents the whole input record when you are not interested in specific fields. Here are some more examples: - $ awk '$1 ~ /foo/ { print $0 }' BBS-list - -| fooey 555-1234 2400/1200/300 B - -| foot 555-6699 1200/300 B - -| macfoo 555-6480 1200/300 A - -| sabafoo 555-2127 1200/300 C + $ awk '$1 ~ /li/ { print $0 }' mail-list + -| Amelia 555-5553 amelia.zodiacusque@gmail.com F + -| Julie 555-6699 julie.perscrutabor@skeeve.com F -This example prints each record in the file `BBS-list' whose first -field contains the string `foo'. The operator `~' is called a -"matching operator" (*note Regexp Usage::); it tests whether a string -(here, the field `$1') matches a given regular expression. +This example prints each record in the file `mail-list' whose first +field contains the string `li'. The operator `~' is called a "matching +operator" (*note Regexp Usage::); it tests whether a string (here, the +field `$1') matches a given regular expression. - By contrast, the following example looks for `foo' in _the entire + By contrast, the following example looks for `li' in _the entire record_ and prints the first field and the last field for each matching input record: - $ awk '/foo/ { print $1, $NF }' BBS-list - -| fooey B - -| foot B - -| macfoo A - -| sabafoo C + $ awk '/li/ { print $1, $NF }' mail-list + -| Amelia F + -| Broderick R + -| Julie F + -| Samuel A ---------- Footnotes ---------- @@ -4196,16 +4206,16 @@ For the twentieth record, field number 20 is printed; most likely, the record has fewer than 20 fields, so this prints a blank line. Here is another example of using expressions as field numbers: - awk '{ print $(2*2) }' BBS-list + awk '{ print $(2*2) }' mail-list `awk' evaluates the expression `(2*2)' and uses its value as the number of the field to print. The `*' sign represents multiplication, so the expression `2*2' evaluates to four. The parentheses are used so that the multiplication is done before the `$' operation; they are necessary whenever there is a binary operator in the field-number -expression. This example, then, prints the hours of operation (the -fourth field) for every line of the file `BBS-list'. (All of the `awk' -operators are listed, in order of decreasing precedence, in *note +expression. This example, then, prints the type of relationship (the +fourth field) for every line of the file `mail-list'. (All of the +`awk' operators are listed, in order of decreasing precedence, in *note Precedence::.) If the field number you compute is zero, you get the entire record. @@ -4602,53 +4612,46 @@ type `-F\t' at the shell, without any quotes, the `\' gets deleted, so TABs and not `t's. Use `-v FS="t"' or `-F"[t]"' on the command line if you really do want to separate your fields with `t's. - As an example, let's use an `awk' program file called `baud.awk' -that contains the pattern `/300/' and the action `print $1': + As an example, let's use an `awk' program file called `edu.awk' that +contains the pattern `/edu/' and the action `print $1': - /300/ { print $1 } + /edu/ { print $1 } Let's also set `FS' to be the `-' character and run the program on -the file `BBS-list'. The following command prints a list of the names -of the bulletin boards that operate at 300 baud and the first three +the file `mail-list'. The following command prints a list of the names +of the people that work at or attend a university, and the first three digits of their phone numbers: - $ awk -F- -f baud.awk BBS-list - -| aardvark 555 - -| alpo - -| barfly 555 - -| bites 555 - -| camelot 555 - -| core 555 - -| fooey 555 - -| foot 555 - -| macfoo 555 - -| sdace 555 - -| sabafoo 555 - -Note the second line of output. The second line in the original file + $ awk -F- -f edu.awk mail-list + -| Fabius 555 + -| Samuel 555 + -| Jean + +Note the third line of output. The third line in the original file looked like this: - alpo-net 555-3412 2400/1200/300 A + Jean-Paul 555-2127 jeanpaul.campanorum@nyu.edu R - The `-' as part of the system's name was used as the field + The `-' as part of the person's name was used as the field separator, instead of the `-' in the phone number that was originally intended. This demonstrates why you have to be careful in choosing your field and record separators. Perhaps the most common use of a single character as the field separator occurs when processing the Unix system password file. On -many Unix systems, each user has a separate entry in the system password -file, one line per user. The information in these lines is separated -by colons. The first field is the user's login name and the second is -the user's (encrypted or shadow) password. A password file entry might -look like this: +many Unix systems, each user has a separate entry in the system +password file, one line per user. The information in these lines is +separated by colons. The first field is the user's login name and the +second is the user's encrypted or shadow password. (A shadow password +is indicated by the presence of a single `x' in the second field.) A +password file entry might look like this: - arnold:xyzzy:2076:10:Arnold Robbins:/home/arnold:/bin/bash + arnold:x:2076:10:Arnold Robbins:/home/arnold:/bin/bash The following program searches the system password file and prints -the entries for users who have no password: +the entries for users whose full name is not indicated: - awk -F: '$2 == ""' /etc/passwd + awk -F: '$5 == ""' /etc/passwd File: gawk.info, Node: Full Line Fields, Next: Field Splitting Summary, Prev: Command Line Field Separator, Up: Field Separators @@ -5834,13 +5837,29 @@ prints the first and second fields of each input record, separated by a semicolon, with a blank line added after each newline: $ awk 'BEGIN { OFS = ";"; ORS = "\n\n" } - > { print $1, $2 }' BBS-list - -| aardvark;555-5553 + > { print $1, $2 }' mail-list + -| Amelia;555-5553 -| - -| alpo-net;555-3412 + -| Anthony;555-3412 + -| + -| Becky;555-7685 + -| + -| Bill;555-1675 + -| + -| Broderick;555-0542 + -| + -| Camilla;555-2912 + -| + -| Fabius;555-1234 + -| + -| Julie;555-6699 + -| + -| Martin;555-6480 + -| + -| Samuel;555-3430 + -| + -| Jean-Paul;555-2127 -| - -| barfly;555-7685 - ... If the value of `ORS' does not contain a newline, the program's output runs together on a single line. @@ -6209,25 +6228,25 @@ File: gawk.info, Node: Printf Examples, Prev: Format Modifiers, Up: Printf The following simple example shows how to use `printf' to make an aligned table: - awk '{ printf "%-10s %s\n", $1, $2 }' BBS-list + awk '{ printf "%-10s %s\n", $1, $2 }' mail-list -This command prints the names of the bulletin boards (`$1') in the file -`BBS-list' as a string of 10 characters that are left-justified. It +This command prints the names of the people (`$1') in the file +`mail-list' as a string of 10 characters that are left-justified. It also prints the phone numbers (`$2') next on the line. This produces an aligned two-column table of names and phone numbers, as shown here: - $ awk '{ printf "%-10s %s\n", $1, $2 }' BBS-list - -| aardvark 555-5553 - -| alpo-net 555-3412 - -| barfly 555-7685 - -| bites 555-1675 - -| camelot 555-0542 - -| core 555-2912 - -| fooey 555-1234 - -| foot 555-6699 - -| macfoo 555-6480 - -| sdace 555-3430 - -| sabafoo 555-2127 + $ awk '{ printf "%-10s %s\n", $1, $2 }' mail-list + -| Amelia 555-5553 + -| Anthony 555-3412 + -| Becky 555-7685 + -| Bill 555-1675 + -| Broderick 555-0542 + -| Camilla 555-2912 + -| Fabius 555-1234 + -| Julie 555-6699 + -| Martin 555-6480 + -| Samuel 555-3430 + -| Jean-Paul 555-2127 In this case, the phone numbers had to be printed as strings because the numbers are separated by a dash. Printing the phone numbers as @@ -6245,14 +6264,14 @@ beginning of the `awk' program: awk 'BEGIN { print "Name Number" print "---- ------" } - { printf "%-10s %s\n", $1, $2 }' BBS-list + { printf "%-10s %s\n", $1, $2 }' mail-list The above example mixes `print' and `printf' statements in the same program. Using just `printf' statements can produce the same results: awk 'BEGIN { printf "%-10s %s\n", "Name", "Number" printf "%-10s %s\n", "----", "------" } - { printf "%-10s %s\n", $1, $2 }' BBS-list + { printf "%-10s %s\n", $1, $2 }' mail-list Printing each column heading with the same format specification used for the column elements ensures that the headings are aligned just like @@ -6264,7 +6283,7 @@ be emphasized by storing it in a variable, like this: awk 'BEGIN { format = "%-10s %s\n" printf format, "Name", "Number" printf format, "----", "------" } - { printf format, $1, $2 }' BBS-list + { printf format, $1, $2 }' mail-list At this point, it would be a worthwhile exercise to use the `printf' statement to line up the headings and table data for the @@ -6304,19 +6323,19 @@ work identically for `printf': the same OUTPUT-FILE do not erase OUTPUT-FILE, but append to it. (This is different from how you use redirections in shell scripts.) If OUTPUT-FILE does not exist, it is created. For example, here - is how an `awk' program can write a list of BBS names to one file - named `name-list', and a list of phone numbers to another file + is how an `awk' program can write a list of peoples' names to one + file named `name-list', and a list of phone numbers to another file named `phone-list': $ awk '{ print $2 > "phone-list" - > print $1 > "name-list" }' BBS-list + > print $1 > "name-list" }' mail-list $ cat phone-list -| 555-5553 -| 555-3412 ... $ cat name-list - -| aardvark - -| alpo-net + -| Amelia + -| Anthony ... Each output file contains one name or number per line. @@ -6337,12 +6356,12 @@ work identically for `printf': The redirection argument COMMAND is actually an `awk' expression. Its value is converted to a string whose contents give the shell command to be run. For example, the following produces two files, - one unsorted list of BBS names, and one list sorted in reverse + one unsorted list of peoples' names, and one list sorted in reverse alphabetical order: awk '{ print $1 > "names.unsorted" command = "sort -r > names.sorted" - print $1 | command }' BBS-list + print $1 | command }' mail-list The unsorted list is written with an ordinary redirection, while the sorted list is written by piping through the `sort' utility. @@ -7072,16 +7091,16 @@ assignment is performed at a time determined by its position among the input file arguments--after the processing of the preceding input file argument. For example: - awk '{ print $n }' n=4 inventory-shipped n=2 BBS-list + awk '{ print $n }' n=4 inventory-shipped n=2 mail-list prints the value of field number `n' for all input records. Before the first file is read, the command line sets the variable `n' equal to four. This causes the fourth field to be printed in lines from `inventory-shipped'. After the first file has finished, but before the second file is started, `n' is set to two, so that the second field is -printed in lines from `BBS-list': +printed in lines from `mail-list': - $ awk '{ print $n }' n=4 inventory-shipped n=2 BBS-list + $ awk '{ print $n }' n=4 inventory-shipped n=2 mail-list -| 15 -| 24 ... @@ -7342,17 +7361,17 @@ a specific operator to represent it. Instead, concatenation is performed by writing expressions next to one another, with no operator. For example: - $ awk '{ print "Field number one: " $1 }' BBS-list - -| Field number one: aardvark - -| Field number one: alpo-net + $ awk '{ print "Field number one: " $1 }' mail-list + -| Field number one: Amelia + -| Field number one: Anthony ... Without the space in the string constant after the `:', the line runs together. For example: - $ awk '{ print "Field number one:" $1 }' BBS-list - -| Field number one:aardvark - -| Field number one:alpo-net + $ awk '{ print "Field number one:" $1 }' mail-list + -| Field number one:Amelia + -| Field number one:Anthony ... Because string concatenation does not have an explicit operator, it @@ -7998,9 +8017,9 @@ Boolean operators are: `BOOLEAN1 && BOOLEAN2' True if both BOOLEAN1 and BOOLEAN2 are true. For example, the following statement prints the current input record if it contains - both `2400' and `foo': + both `edu' and `li': - if ($0 ~ /2400/ && $0 ~ /foo/) print + if ($0 ~ /edu/ && $0 ~ /li/) print The subexpression BOOLEAN2 is evaluated only if BOOLEAN1 is true. This can make a difference when BOOLEAN2 contains expressions that @@ -8011,9 +8030,9 @@ Boolean operators are: `BOOLEAN1 || BOOLEAN2' True if at least one of BOOLEAN1 or BOOLEAN2 is true. For example, the following statement prints all records in the input - that contain _either_ `2400' or `foo' or both: + that contain _either_ `edu' or `li' or both: - if ($0 ~ /2400/ || $0 ~ /foo/) print + if ($0 ~ /edu/ || $0 ~ /li/) print The subexpression BOOLEAN2 is evaluated only if BOOLEAN1 is false. This can make a difference when BOOLEAN2 contains expressions that @@ -8433,56 +8452,53 @@ operand is either a constant regular expression enclosed in slashes (`/REGEXP/'), or any expression whose string value is used as a dynamic regular expression (*note Computed Regexps::). The following example prints the second field of each input record whose first field is -precisely `foo': +precisely `li': - $ awk '$1 == "foo" { print $2 }' BBS-list + $ awk '$1 == "li" { print $2 }' mail-list -(There is no output, because there is no BBS site with the exact name -`foo'.) Contrast this with the following regular expression match, -which accepts any record with a first field that contains `foo': +(There is no output, because there is no person with the exact name +`li'.) Contrast this with the following regular expression match, which +accepts any record with a first field that contains `li': - $ awk '$1 ~ /foo/ { print $2 }' BBS-list - -| 555-1234 + $ awk '$1 ~ /foo/ { print $2 }' mail-list + -| 555-5553 -| 555-6699 - -| 555-6480 - -| 555-2127 A regexp constant as a pattern is also a special case of an -expression pattern. The expression `/foo/' has the value one if `foo' -appears in the current input record. Thus, as a pattern, `/foo/' -matches any record containing `foo'. +expression pattern. The expression `/li/' has the value one if `li' +appears in the current input record. Thus, as a pattern, `/li/' matches +any record containing `li'. Boolean expressions are also commonly used as patterns. Whether the pattern matches an input record depends on whether its subexpressions match. For example, the following command prints all the records in -`BBS-list' that contain both `2400' and `foo': - - $ awk '/2400/ && /foo/' BBS-list - -| fooey 555-1234 2400/1200/300 B - - The following command prints all records in `BBS-list' that contain -_either_ `2400' or `foo' (or both, of course): - - $ awk '/2400/ || /foo/' BBS-list - -| alpo-net 555-3412 2400/1200/300 A - -| bites 555-1675 2400/1200/300 A - -| fooey 555-1234 2400/1200/300 B - -| foot 555-6699 1200/300 B - -| macfoo 555-6480 1200/300 A - -| sdace 555-3430 2400/1200/300 A - -| sabafoo 555-2127 1200/300 C - - The following command prints all records in `BBS-list' that do _not_ -contain the string `foo': - - $ awk '! /foo/' BBS-list - -| aardvark 555-5553 1200/300 B - -| alpo-net 555-3412 2400/1200/300 A - -| barfly 555-7685 1200/300 A - -| bites 555-1675 2400/1200/300 A - -| camelot 555-0542 300 C - -| core 555-2912 1200/300 C - -| sdace 555-3430 2400/1200/300 A +`mail-list' that contain both `edu' and `li': + + $ awk '/edu/ && /li/' mail-list + -| Samuel 555-3430 samuel.lanceolis@shu.edu A + + The following command prints all records in `mail-list' that contain +_either_ `edu' or `li' (or both, of course): + + $ awk '/edu/ || /li/' mail-list + -| Amelia 555-5553 amelia.zodiacusque@gmail.com F + -| Broderick 555-0542 broderick.aliquotiens@yahoo.com R + -| Fabius 555-1234 fabius.undevicesimus@ucb.edu F + -| Julie 555-6699 julie.perscrutabor@skeeve.com F + -| Samuel 555-3430 samuel.lanceolis@shu.edu A + -| Jean-Paul 555-2127 jeanpaul.campanorum@nyu.edu R + + The following command prints all records in `mail-list' that do +_not_ contain the string `li': + + $ awk '! /li/' mail-list + -| Anthony 555-3412 anthony.asserturo@hotmail.com A + -| Becky 555-7685 becky.algebrarum@gmail.com A + -| Bill 555-1675 bill.drowning@hotmail.com A + -| Camilla 555-2912 camilla.infusarum@skynet.be R + -| Fabius 555-1234 fabius.undevicesimus@ucb.edu F + -| Martin 555-6480 martin.codicibus@hotmail.com A + -| Jean-Paul 555-2127 jeanpaul.campanorum@nyu.edu R The subexpressions of a Boolean operator in a pattern can be constant regular expressions, comparisons, or any other `awk' @@ -8559,6 +8575,10 @@ worked around; range patterns do not combine with other patterns: error--> gawk: cmd. line:1: (/1/,/2/) || /Yes/ error--> gawk: cmd. line:1: ^ syntax error + As a minor point of interest, although it is poor style, POSIX +allows you to put a newline after the comma in a range pattern. +(d.c.) + File: gawk.info, Node: BEGIN/END, Next: BEGINFILE/ENDFILE, Prev: Ranges, Up: Pattern Overview @@ -8589,19 +8609,19 @@ read. Likewise, an `END' rule is executed once only, after all the input is read. For example: $ awk ' - > BEGIN { print "Analysis of \"foo\"" } - > /foo/ { ++n } - > END { print "\"foo\" appears", n, "times." }' BBS-list - -| Analysis of "foo" - -| "foo" appears 4 times. - - This program finds the number of records in the input file `BBS-list' -that contain the string `foo'. The `BEGIN' rule prints a title for the -report. There is no need to use the `BEGIN' rule to initialize the -counter `n' to zero, since `awk' does this automatically (*note -Variables::). The second rule increments the variable `n' every time a -record containing the pattern `foo' is read. The `END' rule prints the -value of `n' at the end of the run. + > BEGIN { print "Analysis of \"li\"" } + > /li/ { ++n } + > END { print "\"li\" appears in", n, "records." }' mail-list + -| Analysis of "li" + -| "li" appears in 4 records. + + This program finds the number of records in the input file +`mail-list' that contain the string `li'. The `BEGIN' rule prints a +title for the report. There is no need to use the `BEGIN' rule to +initialize the counter `n' to zero, since `awk' does this automatically +(*note Variables::). The second rule increments the variable `n' every +time a record containing the pattern `li' is read. The `END' rule +prints the value of `n' at the end of the run. The special patterns `BEGIN' and `END' cannot be used in ranges or with Boolean operators (indeed, they cannot be used with any operators). @@ -8752,7 +8772,7 @@ File: gawk.info, Node: Empty, Prev: BEGINFILE/ENDFILE, Up: Pattern Overview An empty (i.e., nonexistent) pattern is considered to match _every_ input record. For example, the program: - awk '{ print $1 }' BBS-list + awk '{ print $1 }' mail-list prints the first field of every record. @@ -9116,9 +9136,11 @@ File: gawk.info, Node: Switch Statement, Next: Break Statement, Prev: For Sta 7.4.5 The `switch' Statement ---------------------------- -The `switch' statement allows the evaluation of an expression and the -execution of statements based on a `case' match. Case statements are -checked for a match in the order they are defined. If no suitable +This minor node describes a `gawk'-specific feature. + + The `switch' statement allows the evaluation of an expression and +the execution of statements based on a `case' match. Case statements +are checked for a match in the order they are defined. If no suitable `case' is found, the `default' section is executed, if supplied. Each `case' contains a single constant, be it numeric, string, or @@ -9377,12 +9399,12 @@ listed in `ARGV'. standard. See the Austin Group website (http://austingroupbugs.net/view.php?id=607). - The current version of the Brian Kernighan's `awk' (*note Other -Versions::) also supports `nextfile'. However, it doesn't allow the -`nextfile' statement inside function bodies (*note User-defined::). -`gawk' does; a `nextfile' inside a function body reads the next record -and starts processing it with the first rule in the program, just as -any other `nextfile' statement. + The current version of the Brian Kernighan's `awk', and `mawk' +(*note Other Versions::) also support `nextfile'. However, they don't +allow the `nextfile' statement inside function bodies (*note +User-defined::). `gawk' does; a `nextfile' inside a function body +reads the next record and starts processing it with the first rule in +the program, just as any other `nextfile' statement. File: gawk.info, Node: Exit Statement, Prev: Nextfile Statement, Up: Statements @@ -9666,13 +9688,13 @@ with a pound sign (`#'). $ awk 'BEGIN { > for (i = 0; i < ARGC; i++) > print ARGV[i] - > }' inventory-shipped BBS-list + > }' inventory-shipped mail-list -| awk -| inventory-shipped - -| BBS-list + -| mail-list `ARGV[0]' contains `awk', `ARGV[1]' contains `inventory-shipped', - and `ARGV[2]' contains `BBS-list'. The value of `ARGC' is three, + and `ARGV[2]' contains `mail-list'. The value of `ARGC' is three, one more than the index of the last element in `ARGV', because the elements are numbered from zero. @@ -9862,8 +9884,8 @@ with a pound sign (`#'). The following additional elements in the array are available to provide information about the MPFR and GMP libraries if your - version of `gawk' supports arbitrary precision numbers (*note - Arbitrary Precision Arithmetic::): + version of `gawk' supports arbitrary precision numbers (*note Gawk + and MPFR::): `PROCINFO["mpfr_version"]' The version of the GNU MPFR library. @@ -9942,7 +9964,7 @@ with a pound sign (`#'). the `delete' statement with the `SYMTAB' array. You may use an index for `SYMTAB' that is not a predefined - identifer: + identifier: SYMTAB["xxx"] = 5 print SYMTAB["xxx"] @@ -10008,13 +10030,13 @@ information contained in `ARGC' and `ARGV': $ awk 'BEGIN { > for (i = 0; i < ARGC; i++) > print ARGV[i] - > }' inventory-shipped BBS-list + > }' inventory-shipped mail-list -| awk -| inventory-shipped - -| BBS-list + -| mail-list In this example, `ARGV[0]' contains `awk', `ARGV[1]' contains -`inventory-shipped', and `ARGV[2]' contains `BBS-list'. Notice that +`inventory-shipped', and `ARGV[2]' contains `mail-list'. Notice that the `awk' program is not entered in `ARGV'. The other command-line options, with their arguments, are also not entered. This includes variable assignments done with the `-v' option (*note Options::). @@ -11261,9 +11283,10 @@ pound sign (`#'): SOURCE is duplicated into DEST. DEST is then sorted, leaving the indices of SOURCE unchanged. - When comparing strings, `IGNORECASE' affects the sorting. If the - SOURCE array contains subarrays as values (*note Arrays of - Arrays::), they will come last, after all scalar values. + When comparing strings, `IGNORECASE' affects the sorting (*note + Array Sorting Functions::). If the SOURCE array contains + subarrays as values (*note Arrays of Arrays::), they will come + last, after all scalar values. For example, if the contents of `a' are as follows: @@ -11302,7 +11325,7 @@ pound sign (`#'): `$0'. It returns the modified string as the result of the function and the original target string is _not_ changed. - `gensub()' is a general substitution function. It's purpose is to + `gensub()' is a general substitution function. Its purpose is to provide more features than the standard `sub()' and `gsub()' functions. @@ -11978,10 +12001,10 @@ parameters are enclosed in square brackets ([ ]): function--`gawk' also buffers its output and the `fflush()' function forces `gawk' to flush its buffers. - `fflush()' was added to Brian Kernighan's version of `awk' in 1994. - For over two decades, it was not part of the POSIX standard. As - of December, 2012, it was accepted for inclusion into the POSIX - standard. See the Austin Group website + `fflush()' was added to Brian Kernighan's version of `awk' in + April of 1992. For two decades, it was not part of the POSIX + standard. As of December, 2012, it was accepted for inclusion + into the POSIX standard. See the Austin Group website (http://austingroupbugs.net/view.php?id=634). POSIX standardizes `fflush()' as follows: If there is no argument, @@ -12184,7 +12207,8 @@ enclosed in square brackets ([ ]): Variables::). The default string value is `"%a %b %e %H:%M:%S %Z %Y"'. This format string produces output that is equivalent to that of the `date' utility. You can assign - a new value to `PROCINFO["strftime"]' to change the default format. + a new value to `PROCINFO["strftime"]' to change the default + format; see below for the various format directives. `systime()' Return the current time as the number of seconds since the system @@ -12597,7 +12621,7 @@ of Arrays::). traversing a multidimensional array: you can test if an element is itself an array or not. The second is inside the body of a user-defined function (not discussed yet; *note User-defined::), to -test if a paramater is an array or not. +test if a parameter is an array or not. Note, however, that using `isarray()' at the global level to test variables makes no sense. Since you are the one writing the program, you @@ -12698,7 +12722,7 @@ a parameter with the same name as the function itself. In addition, according to the POSIX standard, function parameters cannot have the same name as one of the special built-in variables (*note Built-in Variables::. Not all versions of `awk' enforce this -restriction. +restriction.) The BODY-OF-FUNCTION consists of `awk' statements. It is the most important part of the definition, because it says what the function @@ -12741,8 +12765,8 @@ function. When this happens, we say the function is "recursive". The act of a function calling itself is called "recursion". All the built-in functions return a value to their caller. -User-defined functions can do also, using the `return' statement, which -is described in detail in *note Return Statement::. Many of the +User-defined functions can do so also, using the `return' statement, +which is described in detail in *note Return Statement::. Many of the subsequent examples in this minor node use the `return' statement. In many `awk' implementations, including `gawk', the keyword @@ -12812,7 +12836,8 @@ elements in an array and start over with a new list of elements (*note Delete::). Instead of having to repeat this loop everywhere that you need to clear out an array, your program can just call `delarray'. (This guarantees portability. The use of `delete ARRAY' to delete the -contents of an entire array is a nonstandard extension.) +contents of an entire array is a recent(1) addition to the POSIX +standard.) The following is an example of a recursive function. It takes a string as an input parameter and returns the string in backwards order. @@ -12852,13 +12877,19 @@ an `awk' version of `ctime()': return strftime(format, ts) } + ---------- Footnotes ---------- + + (1) Late in 2012. + File: gawk.info, Node: Function Caveats, Next: Return Statement, Prev: Function Example, Up: User-defined 9.2.3 Calling User-Defined Functions ------------------------------------ -This section describes how to call a user-defined function. +"Calling a function" means causing the function to run and do its job. +A function call is an expression and its value is the value returned by +the function. * Menu: @@ -12872,16 +12903,12 @@ File: gawk.info, Node: Calling A Function, Next: Variable Scope, Up: Function 9.2.3.1 Writing A Function Call ............................... -"Calling a function" means causing the function to run and do its job. -A function call is an expression and its value is the value returned by -the function. - - A function call consists of the function name followed by the -arguments in parentheses. `awk' expressions are what you write in the -call for the arguments. Each time the call is executed, these -expressions are evaluated, and the values become the actual arguments. -For example, here is a call to `foo()' with three arguments (the first -being a string concatenation): +A function call consists of the function name followed by the arguments +in parentheses. `awk' expressions are what you write in the call for +the arguments. Each time the call is executed, these expressions are +evaluated, and the values become the actual arguments. For example, +here is a call to `foo()' with three arguments (the first being a +string concatenation): foo(x y, "lose", 4 * z) @@ -13276,7 +13303,7 @@ and then a closing right parenthesis, with the addition of a leading `@' character: the_func = "sum" - result = @the_func() # calls the `sum' function + result = @the_func() # calls the sum() function Here is a full program that processes the previously shown data, using indirect function calls. @@ -13427,8 +13454,8 @@ order. Next comes a sorting function. It is parameterized with the starting and ending field numbers and the comparison function. It -builds an array with the data and calls `quicksort' appropriately, and -then formats the results as a single string: +builds an array with the data and calls `quicksort()' appropriately, +and then formats the results as a single string: # do_sort --- sort the data according to `compare' # and return it as a string @@ -13628,7 +13655,7 @@ will be accidentally shared with the user's program. In addition, several of the library functions use a prefix that helps indicate what function or set of functions use the variables--for -example, `_pw_byname' in the user database routines (*note Passwd +example, `_pw_byname()' in the user database routines (*note Passwd Functions::). This convention is recommended, since it even further decreases the chance of inadvertent conflict among variable names. Note that this convention is used equally well for variable names and @@ -13879,9 +13906,9 @@ File: gawk.info, Node: Round Function, Next: Cliff Random Function, Prev: Ass The way `printf' and `sprintf()' (*note Printf::) perform rounding often depends upon the system's C `sprintf()' subroutine. On many -machines, `sprintf()' rounding is "unbiased," which means it doesn't -always round a trailing `.5' up, contrary to naive expectations. In -unbiased rounding, `.5' rounds to even, rather than always up, so 1.5 +machines, `sprintf()' rounding is "unbiased", which means it doesn't +always round a trailing .5 up, contrary to naive expectations. In +unbiased rounding, .5 rounds to even, rather than always up, so 1.5 rounds to 2 but 4.5 rounds to 4. This means that if you are using a format that does rounding (e.g., `"%.0f"'), you should check what your system does. The following function does traditional rounding; it @@ -13915,7 +13942,7 @@ might be useful if your `awk''s `printf' does unbiased rounding: } # test harness - { print $0, round($0) } + # { print $0, round($0) } File: gawk.info, Node: Cliff Random Function, Next: Ordinal Functions, Prev: Round Function, Up: General Functions @@ -13991,8 +14018,8 @@ corresponding character. Both functions are written very nicely in } } - Some explanation of the numbers used by `chr()' is worthwhile. The -most prominent character set in use today is ASCII.(1) Although an + Some explanation of the numbers used by `_ord_init()' is worthwhile. +The most prominent character set in use today is ASCII.(1) Although an 8-bit byte can hold 256 distinct values (from 0 to 255), ASCII only defines characters that use the values from 0 to 127.(2) In the now distant past, at least one minicomputer manufacturer used ASCII, but @@ -14042,7 +14069,7 @@ tests such as used here prohibitively expensive. (2) ASCII has been extended in many countries to use the values from 128 to 255 for country-specific characters. If your system uses these -extensions, you can simplify `_ord_init' to loop from 0 to 255. +extensions, you can simplify `_ord_init()' to loop from 0 to 255. File: gawk.info, Node: Join Function, Next: Getlocaltime Function, Prev: Ordinal Functions, Up: General Functions @@ -14483,7 +14510,7 @@ File: gawk.info, Node: Ignoring Assigns, Prev: Empty Files, Up: Data File Man Occasionally, you might not want `awk' to process command-line variable assignments (*note Assignment Options::). In particular, if you have a -file name that contain an `=' character, `awk' treats the file name as +file name that contains an `=' character, `awk' treats the file name as an assignment, and does not process it. Some users have suggested an additional command-line option for @@ -14979,7 +15006,7 @@ later. The test can only be true for `gawk'. It is false if using `FS' or `FPAT', or on some other `awk' implementation. The code that checks for using `FPAT', using `using_fpat' and -`PROCINFO["FS"]' is similar. +`PROCINFO["FS"]', is similar. The main part of the function uses a loop to read database lines, split the line into fields, and then store the line into each array as @@ -14999,9 +15026,9 @@ create the element with the null string as its value: return _pw_byname[name] } - Similarly, the `getpwuid' function takes a user ID number argument. -If that user number is in the database, it returns the appropriate -line. Otherwise, it returns the null string: + Similarly, the `getpwuid()' function takes a user ID number +argument. If that user number is in the database, it returns the +appropriate line. Otherwise, it returns the null string: function getpwuid(uid) { @@ -15348,8 +15375,8 @@ index and value, use the indirect function call syntax (*note Indirect Calls::) on `process', passing it the index and the value. When calling `walk_array()', you would pass the name of a -user-defined function that expects to receive and index and a value, -and then processes the element. +user-defined function that expects to receive an index and a value, and +then processes the element. File: gawk.info, Node: Sample Programs, Next: Advanced Features, Prev: Library Functions, Up: Top @@ -15610,7 +15637,7 @@ fields to print are `$1', `$3', and `$5'. The intermediate fields are the fields to print, and `t' tracks the complete field list, including filler fields: - function set_charlist( field, i, j, f, g, t, + function set_charlist( field, i, j, f, g, n, m, t, filler, last, len) { field = 1 # count total fields @@ -16014,9 +16041,9 @@ groups in the `PROCINFO' array have the indices `"group1"' through However, we don't know in advance how many of these groups there are. This loop works by starting at one, concatenating the value with -`"group"', and then using `in' to see if that value is in the array. -Eventually, `i' is incremented past the last group in the array and the -loop exits. +`"group"', and then using `in' to see if that value is in the array +(*note Reference to Elements::). Eventually, `i' is incremented past +the last group in the array and the loop exits. The loop is also correct if there are _no_ supplementary groups; then the condition is false the first time it's tested, and the loop @@ -18536,7 +18563,8 @@ regular pipes. ---------- Footnotes ---------- - (1) This is very different from the same operator in the C shell. + (1) This is very different from the same operator in the C shell and +in Bash. File: gawk.info, Node: TCP/IP Networking, Next: Profiling, Prev: Two-way I/O, Up: Advanced Features @@ -18674,56 +18702,64 @@ First, the `awk' program: junk Here is the `awkprof.out' that results from running the `gawk' -profiler on this program and data (this example also illustrates that -`awk' programmers sometimes have to work late): +profiler on this program and data. (This example also illustrates that +`awk' programmers sometimes get up very early in the morning to work.) - # gawk profile, created Sun Aug 13 00:00:15 2000 + # gawk profile, created Thu Feb 27 05:16:21 2014 - # BEGIN block(s) + # BEGIN block(s) - BEGIN { - 1 print "First BEGIN rule" - 1 print "Second BEGIN rule" - } + BEGIN { + 1 print "First BEGIN rule" + } - # Rule(s) + BEGIN { + 1 print "Second BEGIN rule" + } - 5 /foo/ { # 2 - 2 print "matched /foo/, gosh" - 6 for (i = 1; i <= 3; i++) { - 6 sing() - } - } + # Rule(s) - 5 { - 5 if (/foo/) { # 2 - 2 print "if is true" - 3 } else { - 3 print "else is true" - } - } + 5 /foo/ { # 2 + 2 print "matched /foo/, gosh" + 6 for (i = 1; i <= 3; i++) { + 6 sing() + } + } + + 5 { + 5 if (/foo/) { # 2 + 2 print "if is true" + 3 } else { + 3 print "else is true" + } + } - # END block(s) + # END block(s) - END { - 1 print "First END rule" - 1 print "Second END rule" - } + END { + 1 print "First END rule" + } + + END { + 1 print "Second END rule" + } - # Functions, listed alphabetically - 6 function sing(dummy) - { - 6 print "I gotta be me!" - } + # Functions, listed alphabetically + + 6 function sing(dummy) + { + 6 print "I gotta be me!" + } This example illustrates many of the basic features of profiling output. They are as follows: - * The program is printed in the order `BEGIN' rule, `BEGINFILE' rule, - pattern/action rules, `ENDFILE' rule, `END' rule and functions, - listed alphabetically. Multiple `BEGIN' and `END' rules are - merged together, as are multiple `BEGINFILE' and `ENDFILE' rules. + * The program is printed in the order `BEGIN' rules, `BEGINFILE' + rules, pattern/action rules, `ENDFILE' rules, `END' rules and + functions, listed alphabetically. Multiple `BEGIN' and `END' + rules retain their separate identities, as do multiple `BEGINFILE' + and `ENDFILE' rules. * Pattern-action rules have two counts. The first count, to the left of the rule, shows how many times the rule's pattern was @@ -18774,8 +18810,7 @@ you typed when you wrote it. This is because `gawk' creates the profiled version by "pretty printing" its internal representation of the program. The advantage to this is that `gawk' can produce a standard representation. The disadvantage is that all source-code -comments are lost, as are the distinctions among multiple `BEGIN', -`END', `BEGINFILE', and `ENDFILE' rules. Also, things such as: +comments are lost. Also, things such as: /foo/ @@ -18834,6 +18869,9 @@ by the `Ctrl-<\>' key. called this way, `gawk' "pretty prints" the program into `awkprof.out', without any execution counts. + NOTE: The `--pretty-print' option still runs your program. This + will change in the next major release. + File: gawk.info, Node: Internationalization, Next: Debugger, Prev: Advanced Features, Up: Top @@ -19127,9 +19165,9 @@ File: gawk.info, Node: Translator i18n, Next: I18N Example, Prev: Programmer =============================== Once a program's translatable strings have been marked, they must be -extracted to create the initial `.po' file. As part of translation, it -is often helpful to rearrange the order in which arguments to `printf' -are output. +extracted to create the initial `.pot' file. As part of translation, +it is often helpful to rearrange the order in which arguments to +`printf' are output. `gawk''s `--gen-pot' command-line option extracts the messages and is discussed next. After that, `printf''s ability to rearrange the @@ -19202,7 +19240,7 @@ second: $ gawk 'BEGIN { > string = "Dont Panic" - > printf _"%2$d characters live in \"%1$s\"\n", + > printf "%2$d characters live in \"%1$s\"\n", > string, length(string) > }' -| 10 characters live in "Dont Panic" @@ -19227,7 +19265,7 @@ precision capability: `gawk' does not allow you to mix regular format specifiers and those with positional specifiers in the same string: - $ gawk 'BEGIN { printf _"%d %3$s\n", 1, 2, "hi" }' + $ gawk 'BEGIN { printf "%d %3$s\n", 1, 2, "hi" }' error--> gawk: cmd. line:1: fatal: must use `count$' on all formats or none NOTE: There are some pathological cases that `gawk' may fail to @@ -19589,7 +19627,7 @@ File: gawk.info, Node: Debugger Invocation, Next: Finding The Bug, Up: Sample 14.2.1 How to Start the Debugger -------------------------------- -Starting the debugger is almost exactly like running `awk', except you +Starting the debugger is almost exactly like running `gawk', except you have to pass an additional option `--debug' or the corresponding short option `-D'. The file(s) containing the program and any supporting code are given on the command line as arguments to one or more `-f' @@ -19702,8 +19740,8 @@ our test input above. Let's look at `NR': -| NR = number (2) So we can see that `are_equal()' was only called for the second record -of the file. Of course, this is because our program contained a rule -for `NR == 1': +of the file. Of course, this is because our program contains a rule for +`NR == 1': NR == 1 { last = $0 @@ -21144,11 +21182,15 @@ need it. arbitrary precision arithmetic. The easiest way to find out is to look at the output of the following command: - $ gawk --version - -| GNU Awk 4.1.0, API: 1.0 (GNU MPFR 3.1.0-p3, GNU MP 5.0.2) - -| Copyright (C) 1989, 1991-2013 Free Software Foundation. + $ ./gawk --version + -| GNU Awk 4.1.1, API: 1.1 (GNU MPFR 3.1.0-p3, GNU MP 5.0.2) + -| Copyright (C) 1989, 1991-2014 Free Software Foundation. ... +(You may see different version numbers than what's shown here. That's +OK; what's important is to see that GNU MPFR and GNU MP are listed in +the output.) + `gawk' uses the GNU MPFR (http://www.mpfr.org) and GNU MP (http://gmplib.org) (GMP) libraries for arbitrary precision arithmetic on numbers. So if you do not see the names of these libraries in the @@ -21518,7 +21560,7 @@ floating-point value to begin with: gawk -M 'BEGIN { n = 13.0; print n % 2.0 }' - Note that for the particular example above, there is likely best to + Note that for the particular example above, it is likely best to just use the following: gawk -M 'BEGIN { n = 13; print n % 2 }' @@ -21722,6 +21764,7 @@ This (rather large) minor node describes the API in detail. * Extension API Functions Introduction:: Introduction to the API functions. * General Data Types:: The data types. * Requesting Values:: How to get a value. +* Memory Allocation Functions:: Functions for allocating memory. * Constructor Functions:: Functions for creating values. * Registration Functions:: Functions to register things with `gawk'. @@ -21770,6 +21813,8 @@ operations: * Symbol table access: retrieving a global variable, creating one, or changing one. + * Allocating, reallocating, and releasing memory. + * Creating and releasing cached values; this provides an efficient way to use values for multiple variables and can be a big performance win. @@ -21798,10 +21843,8 @@ operations: `EOF' `<stdio.h>' `FILE' `<stdio.h>' `NULL' `<stddef.h>' - `malloc()' `<stdlib.h>' `memcpy()' `<string.h>' `memset()' `<string.h>' - `realloc()' `<stdlib.h>' `size_t' `<sys/types.h>' `struct stat' `<sys/stat.h>' @@ -21827,7 +21870,9 @@ operations: * All pointers filled in by `gawk' are to memory managed by `gawk' and should be treated by the extension as read-only. Memory for _all_ strings passed into `gawk' from the extension _must_ come - from `malloc()' and is managed by `gawk' from then on. + from calling the API-provided function pointers `api_malloc()', + `api_calloc()' or `api_realloc()', and is managed by `gawk' from + then on. * The API defines several simple `struct's that map values as seen from `awk'. A value can be a `double', a string, or an array (as @@ -21899,7 +21944,9 @@ that use them. `} awk_string_t;' This represents a mutable string. `gawk' owns the memory pointed to if it supplied the value. Otherwise, it takes ownership of the - memory pointed to. *Such memory must come from `malloc()'!* + memory pointed to. *Such memory must come from calling the + API-provided function pointers `api_malloc()', `api_calloc()', or + `api_realloc()'!* As mentioned earlier, strings are maintained using the current multibyte encoding. @@ -22004,7 +22051,7 @@ the value. See also the entry for "Cookie" in the *note Glossary::. -File: gawk.info, Node: Requesting Values, Next: Constructor Functions, Prev: General Data Types, Up: Extension API Description +File: gawk.info, Node: Requesting Values, Next: Memory Allocation Functions, Prev: General Data Types, Up: Extension API Description 16.4.3 Requesting Values ------------------------ @@ -22037,46 +22084,43 @@ Requested: Scalar Scalar Scalar false false Table 16.1: Value Types Returned -File: gawk.info, Node: Constructor Functions, Next: Registration Functions, Prev: Requesting Values, Up: Extension API Description +File: gawk.info, Node: Memory Allocation Functions, Next: Constructor Functions, Prev: Requesting Values, Up: Extension API Description -16.4.4 Constructor Functions and Convenience Macros ---------------------------------------------------- +16.4.4 Memory Allocation Functions and Convenience Macros +--------------------------------------------------------- -The API provides a number of "constructor" functions for creating -string and numeric values, as well as a number of convenience macros. -This node presents them all as function prototypes, in the way that -extension code would use them. +The API provides a number of "memory allocation" functions for +allocating memory that can be passed to `gawk', as well as a number of +convenience macros. -`static inline awk_value_t *' -`make_const_string(const char *string, size_t length, awk_value_t *result)' - This function creates a string value in the `awk_value_t' variable - pointed to by `result'. It expects `string' to be a C string - constant (or other string data), and automatically creates a - _copy_ of the data for storage in `result'. It returns `result'. +`void *gawk_malloc(size_t size);' + Call `gawk'-provided `api_malloc()' to allocate storage that may + be passed to `gawk'. -`static inline awk_value_t *' -`make_malloced_string(const char *string, size_t length, awk_value_t *result)' - This function creates a string value in the `awk_value_t' variable - pointed to by `result'. It expects `string' to be a `char *' value - pointing to data previously obtained from `malloc()'. The idea here - is that the data is passed directly to `gawk', which assumes - responsibility for it. It returns `result'. +`void *gawk_calloc(size_t nmemb, size_t size);' + Call `gawk'-provided `api_calloc()' to allocate storage that may + be passed to `gawk'. -`static inline awk_value_t *' -`make_null_string(awk_value_t *result)' - This specialized function creates a null string (the "undefined" - value) in the `awk_value_t' variable pointed to by `result'. It - returns `result'. +`void *gawk_realloc(void *ptr, size_t size);' + Call `gawk'-provided `api_realloc()' to allocate storage that may + be passed to `gawk'. -`static inline awk_value_t *' -`make_number(double num, awk_value_t *result)' - This function simply creates a numeric value in the `awk_value_t' - variable pointed to by `result'. +`void gawk_free(void *ptr);' + Call `gawk'-provided `api_free()' to release storage that was + allocated with `gawk_malloc()', `gawk_calloc()' or + `gawk_realloc()'. - Two convenience macros may be used for allocating storage from -`malloc()' and `realloc()'. If the allocation fails, they cause `gawk' -to exit with a fatal error message. They should be used as if they were -procedure calls that do not return a value. + The API has to provide these functions because it is possible for an +extension to be compiled and linked against a different version of the +C library than was used for the `gawk' executable.(1) If `gawk' were to +use its version of `free()' when the memory came from an unrelated +version of `malloc()', unexpected behavior would likely result. + + Two convenience macros may be used for allocating storage from the +API-provided function pointers `api_malloc()' and `api_realloc()'. If +the allocation fails, they cause `gawk' to exit with a fatal error +message. They should be used as if they were procedure calls that do +not return a value. `#define emalloc(pointer, type, size, message) ...' The arguments to this macro are as follows: @@ -22085,7 +22129,7 @@ procedure calls that do not return a value. `type' The type of the pointer variable, used to create a cast for - the call to `malloc()'. + the call to `api_malloc()'. `size' The total number of bytes to be allocated. @@ -22105,14 +22149,57 @@ procedure calls that do not return a value. make_malloced_string(message, strlen(message), & result); `#define erealloc(pointer, type, size, message) ...' - This is like `emalloc()', but it calls `realloc()', instead of - `malloc()'. The arguments are the same as for the `emalloc()' + This is like `emalloc()', but it calls `api_realloc()', instead of + `api_malloc()'. The arguments are the same as for the `emalloc()' macro. + ---------- Footnotes ---------- + + (1) This is more common on MS-Windows systems, but can happen on +Unix-like systems as well. + + +File: gawk.info, Node: Constructor Functions, Next: Registration Functions, Prev: Memory Allocation Functions, Up: Extension API Description + +16.4.5 Constructor Functions +---------------------------- + +The API provides a number of "constructor" functions for creating +string and numeric values, as well as a number of convenience macros. +This node presents them all as function prototypes, in the way that +extension code would use them. + +`static inline awk_value_t *' +`make_const_string(const char *string, size_t length, awk_value_t *result)' + This function creates a string value in the `awk_value_t' variable + pointed to by `result'. It expects `string' to be a C string + constant (or other string data), and automatically creates a + _copy_ of the data for storage in `result'. It returns `result'. + +`static inline awk_value_t *' +`make_malloced_string(const char *string, size_t length, awk_value_t *result)' + This function creates a string value in the `awk_value_t' variable + pointed to by `result'. It expects `string' to be a `char *' value + pointing to data previously obtained from the api-provided + functions `api_malloc()', `api_calloc()' or `api_realloc()'. The + idea here is that the data is passed directly to `gawk', which + assumes responsibility for it. It returns `result'. + +`static inline awk_value_t *' +`make_null_string(awk_value_t *result)' + This specialized function creates a null string (the "undefined" + value) in the `awk_value_t' variable pointed to by `result'. It + returns `result'. + +`static inline awk_value_t *' +`make_number(double num, awk_value_t *result)' + This function simply creates a numeric value in the `awk_value_t' + variable pointed to by `result'. + File: gawk.info, Node: Registration Functions, Next: Printing Messages, Prev: Constructor Functions, Up: Extension API Description -16.4.5 Registration Functions +16.4.6 Registration Functions ----------------------------- This minor node describes the API functions for registering parts of @@ -22130,7 +22217,7 @@ your extension with `gawk'. File: gawk.info, Node: Extension Functions, Next: Exit Callback Functions, Up: Registration Functions -16.4.5.1 Registering An Extension Function +16.4.6.1 Registering An Extension Function .......................................... Extension functions are described by the following record: @@ -22155,8 +22242,10 @@ Extension functions are described by the following record: `awk_value_t *(*function)(int num_actual_args, awk_value_t *result);' This is a pointer to the C function that provides the desired functionality. The function must fill in the result with either a - number or a string. `awk' takes ownership of any string memory. - As mentioned earlier, string memory *must* come from `malloc()'. + number or a string. `gawk' takes ownership of any string memory. + As mentioned earlier, string memory *must* come from the + api-provided functions `api_malloc()', `api_calloc()' or + `api_realloc()'. The `num_actual_args' argument tells the C function how many actual parameters were passed from the calling `awk' code. @@ -22182,7 +22271,7 @@ register it with `gawk' using this API function: File: gawk.info, Node: Exit Callback Functions, Next: Extension Version String, Prev: Extension Functions, Up: Registration Functions -16.4.5.2 Registering An Exit Callback Function +16.4.6.2 Registering An Exit Callback Function .............................................. An "exit callback" function is a function that `gawk' calls before it @@ -22211,7 +22300,7 @@ order--that is, in the reverse order in which they are registered with File: gawk.info, Node: Extension Version String, Next: Input Parsers, Prev: Exit Callback Functions, Up: Registration Functions -16.4.5.3 Registering An Extension Version String +16.4.6.3 Registering An Extension Version String ................................................ You can register a version string which indicates the name and version @@ -22227,7 +22316,7 @@ invoked with the `--version' option. File: gawk.info, Node: Input Parsers, Next: Output Wrappers, Prev: Extension Version String, Up: Registration Functions -16.4.5.4 Customized Input Parsers +16.4.6.4 Customized Input Parsers ................................. By default, `gawk' reads text files as its input. It uses the value of @@ -22449,7 +22538,7 @@ whether or not to activate an input parser (*note BEGINFILE/ENDFILE::). File: gawk.info, Node: Output Wrappers, Next: Two-way processors, Prev: Input Parsers, Up: Registration Functions -16.4.5.5 Customized Output Wrappers +16.4.6.5 Customized Output Wrappers ................................... An "output wrapper" is the mirror image of an input parser. It allows @@ -22556,7 +22645,7 @@ normally. File: gawk.info, Node: Two-way processors, Prev: Output Wrappers, Up: Registration Functions -16.4.5.6 Customized Two-way Processors +16.4.6.6 Customized Two-way Processors ...................................... A "two-way processor" combines an input parser and an output wrapper for @@ -22609,7 +22698,7 @@ can take this" and "take over for this" functions, File: gawk.info, Node: Printing Messages, Next: Updating `ERRNO', Prev: Registration Functions, Up: Extension API Description -16.4.6 Printing Messages +16.4.7 Printing Messages ------------------------ You can print different kinds of warning messages from your extension, @@ -22640,7 +22729,7 @@ the pity. File: gawk.info, Node: Updating `ERRNO', Next: Accessing Parameters, Prev: Printing Messages, Up: Extension API Description -16.4.7 Updating `ERRNO' +16.4.8 Updating `ERRNO' ----------------------- The following functions allow you to update the `ERRNO' variable: @@ -22661,7 +22750,7 @@ The following functions allow you to update the `ERRNO' variable: File: gawk.info, Node: Accessing Parameters, Next: Symbol Table Access, Prev: Updating `ERRNO', Up: Extension API Description -16.4.8 Accessing and Updating Parameters +16.4.9 Accessing and Updating Parameters ---------------------------------------- Two functions give you access to the arguments (parameters) passed to @@ -22687,8 +22776,8 @@ your extension function. They are: File: gawk.info, Node: Symbol Table Access, Next: Array Manipulation, Prev: Accessing Parameters, Up: Extension API Description -16.4.9 Symbol Table Access --------------------------- +16.4.10 Symbol Table Access +--------------------------- Two sets of routines provide access to global variables, and one set allows you to create and release cached values. @@ -22702,8 +22791,8 @@ allows you to create and release cached values. File: gawk.info, Node: Symbol table by name, Next: Symbol table by cookie, Up: Symbol Table Access -16.4.9.1 Variable Access and Update by Name -........................................... +16.4.10.1 Variable Access and Update by Name +............................................ The following routines provide the ability to access and update global `awk'-level variables by name. In compiler terminology, identifiers of @@ -22735,11 +22824,16 @@ termed a "symbol table". However, with the exception of the `PROCINFO' array, an extension cannot change any of those variables. + NOTE: It is possible for the lookup of `PROCINFO' to fail. This + happens if the `awk' program being run does not reference + `PROCINFO'; in this case `gawk' doesn't bother to create the array + and populate it. + File: gawk.info, Node: Symbol table by cookie, Next: Cached values, Prev: Symbol table by name, Up: Symbol Table Access -16.4.9.2 Variable Access and Update by Cookie -............................................. +16.4.10.2 Variable Access and Update by Cookie +.............................................. A "scalar cookie" is an opaque handle that provides access to a global variable or array. It is an optimization that avoids looking up @@ -22851,8 +22945,8 @@ like this: File: gawk.info, Node: Cached values, Prev: Symbol table by cookie, Up: Symbol Table Access -16.4.9.3 Creating and Using Cached Values -......................................... +16.4.10.3 Creating and Using Cached Values +.......................................... The routines in this section allow you to create and release cached values. As with scalar cookies, in theory, cached values are not @@ -22862,8 +22956,9 @@ variables using `sym_update()' or `sym_update_scalar()', as you like. However, you can understand the point of cached values if you remember that _every_ string value's storage _must_ come from -`malloc()'. If you have 20 variables, all of which have the same -string value, you must create 20 identical copies of the string.(1) +`api_malloc()', `api_calloc()' or `api_realloc()'. If you have 20 +variables, all of which have the same string value, you must create 20 +identical copies of the string.(1) It is clearly more efficient, if possible, to create a value once, and then tell `gawk' to reuse the value for multiple variables. That is @@ -22946,7 +23041,7 @@ using `release_value()'. File: gawk.info, Node: Array Manipulation, Next: Extension API Variables, Prev: Symbol Table Access, Up: Extension API Description -16.4.10 Array Manipulation +16.4.11 Array Manipulation -------------------------- The primary data structure(1) in `awk' is the associative array (*note @@ -22973,7 +23068,7 @@ arrays of arrays (*note General Data Types::). File: gawk.info, Node: Array Data Types, Next: Array Functions, Up: Array Manipulation -16.4.10.1 Array Data Types +16.4.11.1 Array Data Types .......................... The data types associated with arrays are listed below. @@ -23040,7 +23135,7 @@ overuse this term. File: gawk.info, Node: Array Functions, Next: Flattening Arrays, Prev: Array Data Types, Up: Array Manipulation -16.4.10.2 Array Functions +16.4.11.2 Array Functions ......................... The following functions relate to individual array elements. @@ -23066,7 +23161,8 @@ The following functions relate to individual array elements. strings (*note Conversion::); thus using integral values is safest. As with _all_ strings passed into `gawk' from an extension, the - string value of `index' must come from `malloc()', and `gawk' + string value of `index' must come from the API-provided functions + `api_malloc()', `api_calloc()' or `api_realloc()' and `gawk' releases the storage. `awk_bool_t set_array_element(awk_array_t a_cookie,' @@ -23117,7 +23213,7 @@ The following functions relate to individual array elements. File: gawk.info, Node: Flattening Arrays, Next: Creating Arrays, Prev: Array Functions, Up: Array Manipulation -16.4.10.3 Working With All The Elements of an Array +16.4.11.3 Working With All The Elements of an Array ................................................... To "flatten" an array is create a structure that represents the full @@ -23291,7 +23387,7 @@ return value to success, and returns: File: gawk.info, Node: Creating Arrays, Prev: Flattening Arrays, Up: Array Manipulation -16.4.10.4 How To Create and Populate Arrays +16.4.11.4 How To Create and Populate Arrays ........................................... Besides working with arrays created by `awk' code, you can create @@ -23430,7 +23526,7 @@ environment variable.) File: gawk.info, Node: Extension API Variables, Next: Extension API Boilerplate, Prev: Array Manipulation, Up: Extension API Description -16.4.11 API Variables +16.4.12 API Variables --------------------- The API provides two sets of variables. The first provides information @@ -23447,7 +23543,7 @@ information about how `gawk' was invoked. File: gawk.info, Node: Extension Versioning, Next: Extension API Informational Variables, Up: Extension API Variables -16.4.11.1 API Version Constants and Variables +16.4.12.1 API Version Constants and Variables ............................................. The API provides both a "major" and a "minor" version number. The API @@ -23496,7 +23592,7 @@ Boilerplate::). File: gawk.info, Node: Extension API Informational Variables, Prev: Extension Versioning, Up: Extension API Variables -16.4.11.2 Informational Variables +16.4.12.2 Informational Variables ................................. The API provides access to several variables that describe whether the @@ -23532,7 +23628,7 @@ change during execution. File: gawk.info, Node: Extension API Boilerplate, Prev: Extension API Variables, Up: Extension API Description -16.4.12 Boilerplate Code +16.4.13 Boilerplate Code ------------------------ As mentioned earlier (*note Extension Mechanism Outline::), the function @@ -24050,7 +24146,7 @@ declarations and argument checking: awk_array_t array; int ret; struct stat sbuf; - /* default is stat() */ + /* default is lstat() */ int (*statfunc)(const char *path, struct stat *sbuf) = lstat; assert(result != NULL); @@ -24448,12 +24544,16 @@ File: gawk.info, Node: Extension Sample Fnmatch, Next: Extension Sample Fork, This extension provides an interface to the C library `fnmatch()' function. The usage is: - @load "fnmatch" +`@load "fnmatch"' + This is how you load the extension. - result = fnmatch(pattern, string, flags) +`result = fnmatch(pattern, string, flags)' + The return value is zero on success, `FNM_NOMATCH' if the string + did not match the pattern, or a different non-zero value if an + error occurred. - The `fnmatch' extension adds a single function named `fnmatch()', -one constant (`FNM_NOMATCH'), and an array of flag values named `FNM'. + Besides the `fnmatch()' function, the `fnmatch' extension adds one +constant (`FNM_NOMATCH'), and an array of flag values named `FNM'. The arguments to `fnmatch()' are: @@ -24467,10 +24567,6 @@ one constant (`FNM_NOMATCH'), and an array of flag values named `FNM'. Either zero, or the bitwise OR of one or more of the flags in the `FNM' array. - The return value is zero on success, `FNM_NOMATCH' if the string did -not match the pattern, or a different non-zero value if an error -occurred. - The flags are follows: `FNM["CASEFOLD"]' Corresponds to the `FNM_CASEFOLD' flag as defined in @@ -24506,14 +24602,14 @@ The `fork' extension adds three functions, as follows. This is how you load the extension. `pid = fork()' - This function creates a new process. The return value is the zero - in the child and the process-id number of the child in the parent, - or -1 upon error. In the latter case, `ERRNO' indicates the - problem. In the child, `PROCINFO["pid"]' and `PROCINFO["ppid"]' - are updated to reflect the correct values. + This function creates a new process. The return value is zero in + the child and the process-ID number of the child in the parent, or + -1 upon error. In the latter case, `ERRNO' indicates the problem. + In the child, `PROCINFO["pid"]' and `PROCINFO["ppid"]' are updated + to reflect the correct values. `ret = waitpid(pid)' - This function takes a numeric argument, which is the process-id to + This function takes a numeric argument, which is the process-ID to wait for. The return value is that of the `waitpid()' system call. `ret = wait()' @@ -24746,7 +24842,8 @@ File: gawk.info, Node: Extension Sample Readfile, Next: Extension Sample API T 16.7.10 Reading An Entire File ------------------------------ -The `readfile' extension adds a single function named `readfile()': +The `readfile' extension adds a single function named `readfile()', and +an input parser: `@load "readfile"' This is how you load the extension. @@ -24756,6 +24853,12 @@ The `readfile' extension adds a single function named `readfile()': a string containing the entire contents of the requested file. Upon error, the function returns the empty string and sets `ERRNO'. +`BEGIN { PROCINFO["readfile"] = 1 }' + In addition, the extension adds an input parser that is activated + if `PROCINFO["readfile"]' exists. When activated, each input file + is returned in its entirety as `$0'. `RT' is set to the null + string. + Here is an example: @load "readfile" @@ -25603,7 +25706,7 @@ in POSIX `awk', in the order they were added to `gawk'. - The `-i' and `--include' options load `awk' library files. - - The `-l' and `--load' options for load compiled dynamic + - The `-l' and `--load' options load compiled dynamic extensions. - The `-M' and `--bignum' options enable MPFR. @@ -25617,8 +25720,9 @@ in POSIX `awk', in the order they were added to `gawk'. * Support for high precision arithmetic with MPFR. (*note Gawk and MPFR::). - * The `and()', `or()' and `xor()' functions allow any number of - arguments, with a minimum of two (*note Bitwise Functions::). + * The `and()', `or()' and `xor()' functions changed to allow any + number of arguments, with a minimum of two (*note Bitwise + Functions::). * The dynamic extension interface was completely redone (*note Dynamic Extensions::). @@ -25637,18 +25741,18 @@ available versions of `awk' (*note Other Versions::). Feature BWK Awk Mawk GNU Awk -------------------------------------------------------- `\x' Escape sequence X X X -`RS' as regexp X X `FS' as null string X X X `/dev/stdin' special file X X X `/dev/stdout' special file X X X `/dev/stderr' special file X X X -`**' and `**=' operators X X -`fflush()' function X X X -`func' keyword X X -`nextfile' statement X X X `delete' without subscript X X X +`fflush()' function X X X `length()' of an array X X X +`nextfile' statement X X X +`**' and `**=' operators X X +`func' keyword X X `BINMODE' variable X X +`RS' as regexp X X Time related functions X X (Technically speaking, as of late 2012, `fflush()', `delete ARRAY', @@ -25681,7 +25785,7 @@ as working in this fashion, and in particular, would teach that the `[A-Z]' was the "correct" way to match uppercase letters. And indeed, this was true.(1) - The 1993 POSIX standard introduced the idea of locales (*note + The 1992 POSIX standard introduced the idea of locales (*note Locales::). Since many locales include other letters besides the plain twenty-six letters of the American English alphabet, the POSIX standard added character classes (*note Bracket Expressions::) as a way to match @@ -25744,17 +25848,17 @@ of range expressions was _undefined_.(3) By using this lovely technical term, the standard gives license to implementors to implement ranges in whatever way they choose. The `gawk' maintainer chose to apply the pre-POSIX meaning in all cases: -the default regexp matching; with `--traditional', and with `--posix'; +the default regexp matching; with `--traditional' and with `--posix'; in all cases, `gawk' remains POSIX compliant. ---------- Footnotes ---------- (1) And Life was good. - (2) And thus was born the Campain for Rational Range Interpretation -(or RRI). A number of GNU tools, such as `grep' and `sed', have either -implemented this change, or will soon. Thanks to Karl Berry for -coining the phrase "Rational Range Interpretation." + (2) And thus was born the Campaign for Rational Range Interpretation +(or RRI). A number of GNU tools have either implemented this change, or +will soon. Thanks to Karl Berry for coining the phrase "Rational Range +Interpretation." (3) See the standard (http://pubs.opengroup.org/onlinepubs/9699919799/basedefs/V1_chap09.html#tag_09_03_05) @@ -25866,6 +25970,9 @@ Info file, in approximate chronological order: * Anders Wallin helped keep the VMS port going for several years. + * Assaf Gordon contributed the code to implement the `--sandbox' + option. + * John Haque made the following contributions: - The modifications to convert `gawk' into a byte-code @@ -25893,6 +26000,10 @@ Info file, in approximate chronological order: 4.1 was driven primarily by Arnold Robbins and Andrew Schorr, with notable contributions from the rest of the development team. + * Antonio Giovanni Colombo rewrote a number of examples in the early + chapters that were severely dated, for which I am incredibly + grateful. + * Arnold Robbins has been working on `gawk' since 1988, at first helping David Trueman, and as the primary maintainer since around 1994. @@ -25949,7 +26060,7 @@ There are three ways to get GNU software: supported. If you have the `wget' program, you can use a command like the following: - wget http://ftp.gnu.org/gnu/gawk/gawk-4.1.0.tar.gz + wget http://ftp.gnu.org/gnu/gawk/gawk-4.1.1.tar.gz The GNU software archive is mirrored around the world. The up-to-date list of mirror sites is available from the main FSF web site @@ -25968,26 +26079,26 @@ compression programs: `gzip', `bzip2', and `xz'. For simplicity, the rest of these instructions assume you are using the one compressed with the GNU Zip program, `gzip'. - Once you have the distribution (for example, `gawk-4.1.0.tar.gz'), + Once you have the distribution (for example, `gawk-4.1.1.tar.gz'), use `gzip' to expand the file and then use `tar' to extract it. You can use the following pipeline to produce the `gawk' distribution: # Under System V, add 'o' to the tar options - gzip -d -c gawk-4.1.0.tar.gz | tar -xvpf - + gzip -d -c gawk-4.1.1.tar.gz | tar -xvpf - On a system with GNU `tar', you can let `tar' do the decompression for you: - tar -xvpzf gawk-4.1.0.tar.gz + tar -xvpzf gawk-4.1.1.tar.gz -Extracting the archive creates a directory named `gawk-4.1.0' in the +Extracting the archive creates a directory named `gawk-4.1.1' in the current directory. The distribution file name is of the form `gawk-V.R.P.tar.gz'. The V represents the major version of `gawk', the R represents the current release of version V, and the P represents a "patch level", meaning that minor bugs have been fixed in the release. The current patch -level is 0, but when retrieving distributions, you should get the +level is 1, but when retrieving distributions, you should get the version with the highest version, release, and patch level. (Note, however, that patch levels greater than or equal to 70 denote "beta" or nonproduction software; you might not want to retrieve such a version @@ -26197,7 +26308,7 @@ Unix-derived systems, GNU/Linux, BSD-based systems, and the Cygwin environment for MS-Windows. After you have extracted the `gawk' distribution, `cd' to -`gawk-4.1.0'. Like most GNU software, `gawk' is configured +`gawk-4.1.1'. Like most GNU software, `gawk' is configured automatically for your system by running the `configure' program. This program is a Bourne shell script that is generated automatically using GNU `autoconf'. (The `autoconf' software is described fully starting @@ -26236,8 +26347,8 @@ failure is not described there, please send in a bug report (*note Bugs::). Of course, once you've built `gawk', it is likely that you will wish -to install it. To do so, you need to run the command `make check', as -a user with the appropriate permissions. How to do this varies by +to install it. To do so, you need to run the command `make install', +as a user with the appropriate permissions. How to do this varies by system, but on many systems you can use the `sudo' command to do so. The command then becomes `sudo make install'. It is likely that you will be asked for your password, and you will have to have been set up @@ -26520,10 +26631,9 @@ File: gawk.info, Node: PC Using, Next: Cygwin, Prev: PC Testing, Up: PC Inst B.3.1.4 Using `gawk' on PC Operating Systems ............................................ -With the exception of the Cygwin environment, the `|&' operator and -TCP/IP networking (*note TCP/IP Networking::) are not supported for -MS-DOS or MS-Windows. EMX (OS/2 only) does support at least the `|&' -operator. +Under MS-DOS and MS-Windows, the Cygwin and MinGW environments support +both the `|&' operator and TCP/IP networking (*note TCP/IP +Networking::). EMX (OS/2 only) supports at least the `|&' operator. The MS-DOS and MS-Windows versions of `gawk' search for program files as described in *note AWKPATH Variable::. However, semicolons @@ -26616,13 +26726,13 @@ B.3.1.5 Using `gawk' In The Cygwin Environment `gawk' can be built and used "out of the box" under MS-Windows if you are using the Cygwin environment (http://www.cygwin.com). This -environment provides an excellent simulation of Unix, using the GNU -tools, such as Bash, the GNU Compiler Collection (GCC), GNU Make, and -other GNU programs. Compilation and installation for Cygwin is the +environment provides an excellent simulation of GNU/Linux, using the +GNU tools, such as Bash, the GNU Compiler Collection (GCC), GNU Make, +and other GNU programs. Compilation and installation for Cygwin is the same as for a Unix system: - tar -xvpzf gawk-4.1.0.tar.gz - cd gawk-4.1.0 + tar -xvpzf gawk-4.1.1.tar.gz + cd gawk-4.1.1 ./configure make @@ -26630,10 +26740,6 @@ same as for a Unix system: on Cygwin takes considerably longer. However, it does finish, and then the `make' proceeds as usual. - NOTE: The `|&' operator and TCP/IP networking (*note TCP/IP - Networking::) are fully supported in the Cygwin environment. This - is not true for any other environment on MS-Windows. - File: gawk.info, Node: MSYS, Prev: Cygwin, Up: PC Installation @@ -26695,20 +26801,13 @@ available from `https://github.com/endlesssoftware/mmk'. With `ODS-5' volumes and extended parsing enabled, the case of the target parameter may need to be exact. - Older versions of `gawk' could be built with VAX C or GNU C on -VAX/VMS, as well as with DEC C, but that is no longer supported. DEC C -(also briefly known as "Compaq C" and now known as "HP C," but referred -to here as "DEC C") is required. Both `vmsbuild.com' and `descrip.mms' -contain some obsolete support for the older compilers but are set up to -use DEC C by default. - `gawk' has been tested under VAX/VMS 7.3 and Alpha/VMS 7.3-1 using Compaq C V6.4, and Alpha/VMS 7.3, Alpha/VMS 7.3-2, and IA64/VMS 8.3. The most recent builds used HP C V7.3 on Alpha VMS 8.3 and both Alpha and IA64 VMS 8.4 used HP C 7.3.(1) - Work is currently being done for a procedure to build `gawk' and -create a PCSI kit for compatible with the GNV product. + The `[.vms]gawk_build_steps.txt' provides information on how to build +`gawk' into a PCSI kit that is compatible with the GNV product. ---------- Footnotes ---------- @@ -26797,7 +26896,8 @@ add the `gawk' and `awk' to the system wide `DCLTABLES'. The DCL syntax is documented in the `gawk.hlp' file. - Optionally, `gawk.hlp' entry can be loaded into a VMS help library: + Optionally, the `gawk.hlp' entry can be loaded into a VMS help +library: $ LIBRARY/HELP sys$help:helplib [.vms]gawk.hlp @@ -27926,7 +28026,7 @@ D.1 What a Program Does ======================= At the most basic level, the job of a program is to process some input -data and produce results. See *note figure-general-flow::. +data and produce results. See *note figure-general-flow::. _______ +------+ / \ +---------+ @@ -28159,9 +28259,6 @@ Bash The GNU version of the standard shell (the Bourne-Again SHell). See also "Bourne Shell." -BBS - See "Bulletin Board System." - Bit Short for "Binary Digit." All values in computer memory ultimately reduce to binary digits: values that are either zero or @@ -28207,11 +28304,6 @@ Built-in Variable Braces See "Curly Braces." -Bulletin Board System - A computer system allowing users to log in and read and/or leave - messages for other users of the system, much like leaving paper - notes on a bulletin board. - C The system programming language that most GNU software is written in. The `awk' programming language has C-like syntax, and this @@ -28318,8 +28410,8 @@ Dynamic Regular Expression (*Note Computed Regexps::.) Environment - A collection of strings, of the form NAME`='VAL, that each program - has available to it. Users generally place values into the + A collection of strings, of the form NAME`='`val', that each + program has available to it. Users generally place values into the environment in order to provide information to various programs. Typical examples are the environment variables `HOME' and `PATH'. @@ -28734,7 +28826,6 @@ GNU General Public License ************************** Version 3, 29 June 2007 - Copyright (C) 2007 Free Software Foundation, Inc. `http://fsf.org/' Everyone is permitted to copy and distribute verbatim copies of this @@ -29457,7 +29548,6 @@ GNU Free Documentation License ****************************** Version 1.3, 3 November 2008 - Copyright (C) 2000, 2001, 2002, 2007, 2008 Free Software Foundation, Inc. `http://fsf.org/' @@ -29961,17 +30051,17 @@ Index * ! (exclamation point), !~ operator <5>: Computed Regexps. (line 6) * ! (exclamation point), !~ operator <6>: Case-sensitivity. (line 26) * ! (exclamation point), !~ operator: Regexp Usage. (line 19) -* " (double quote) <1>: Quoting. (line 37) -* " (double quote): Read Terminal. (line 25) +* " (double quote) in shell commands: Read Terminal. (line 25) * " (double quote), in regexp constants: Computed Regexps. (line 28) +* " (double quote), in shell commands: Quoting. (line 37) * # (number sign), #! (executable scripts): Executable Scripts. (line 6) * # (number sign), commenting: Comments. (line 6) -* $ (dollar sign): Regexp Operators. (line 35) * $ (dollar sign), $ field operator <1>: Precedence. (line 43) * $ (dollar sign), $ field operator: Fields. (line 19) * $ (dollar sign), incrementing fields and arrays: Increment Ops. (line 30) +* $ (dollar sign), regexp operator: Regexp Operators. (line 35) * % (percent sign), % operator: Precedence. (line 55) * % (percent sign), %= operator <1>: Precedence. (line 95) * % (percent sign), %= operator: Assignment Ops. (line 129) @@ -29979,13 +30069,13 @@ Index * & (ampersand), && operator: Boolean Ops. (line 57) * & (ampersand), gsub()/gensub()/sub() functions and: Gory Details. (line 6) -* ' (single quote) <1>: Quoting. (line 31) -* ' (single quote) <2>: Long. (line 33) * ' (single quote): One-shot. (line 15) +* ' (single quote) in gawk command lines: Long. (line 33) +* ' (single quote), in shell commands: Quoting. (line 31) * ' (single quote), vs. apostrophe: Comments. (line 27) * ' (single quote), with double quotes: Quoting. (line 53) -* () (parentheses) <1>: Profiling. (line 138) -* () (parentheses): Regexp Operators. (line 79) +* () (parentheses), in a profile: Profiling. (line 146) +* () (parentheses), regexp operator: Regexp Operators. (line 79) * * (asterisk), * operator, as multiplication operator: Precedence. (line 55) * * (asterisk), * operator, as regexp operator: Regexp Operators. @@ -29998,12 +30088,12 @@ Index * * (asterisk), **= operator: Assignment Ops. (line 129) * * (asterisk), *= operator <1>: Precedence. (line 95) * * (asterisk), *= operator: Assignment Ops. (line 129) -* + (plus sign): Regexp Operators. (line 102) * + (plus sign), + operator: Precedence. (line 52) * + (plus sign), ++ operator <1>: Precedence. (line 46) * + (plus sign), ++ operator: Increment Ops. (line 11) * + (plus sign), += operator <1>: Precedence. (line 95) * + (plus sign), += operator: Assignment Ops. (line 82) +* + (plus sign), regexp operator: Regexp Operators. (line 102) * , (comma), in range patterns: Ranges. (line 6) * - (hyphen), - operator: Precedence. (line 52) * - (hyphen), -- operator <1>: Precedence. (line 46) @@ -30023,8 +30113,9 @@ Index (line 15) * --disable-nls configuration option: Additional Configuration Options. (line 30) -* --dump-variables option <1>: Library Names. (line 45) * --dump-variables option: Options. (line 93) +* --dump-variables option, using for library functions: Library Names. + (line 45) * --exec option: Options. (line 125) * --field-separator option: Options. (line 21) * --file option: Options. (line 25) @@ -30067,12 +30158,12 @@ Index * -d option: Options. (line 93) * -E option: Options. (line 125) * -e option: Options. (line 117) -* -F option: Command Line Field Separator. - (line 6) * -f option: Options. (line 25) * -F option: Options. (line 21) * -f option: Long. (line 12) * -F option, -Ft sets FS to TAB: Options. (line 301) +* -F option, command line: Command Line Field Separator. + (line 6) * -f option, multiple uses: Options. (line 306) * -g option: Options. (line 147) * -h option: Options. (line 154) @@ -30092,7 +30183,7 @@ Index * -V option: Options. (line 293) * -v option: Options. (line 32) * -W option: Options. (line 46) -* . (period): Regexp Operators. (line 43) +* . (period), regexp operator: Regexp Operators. (line 43) * .gmo files: Explaining gettext. (line 41) * .gmo files, converting from .po: I18N Example. (line 62) * .gmo files, specifying directory of <1>: Programmer i18n. (line 47) @@ -30101,7 +30192,7 @@ Index * .po files: Explaining gettext. (line 36) * .po files, converting to .gmo: I18N Example. (line 62) * .pot files: Explaining gettext. (line 30) -* / (forward slash): Regexp. (line 10) +* / (forward slash) to enclose regular expressions: Regexp. (line 10) * / (forward slash), / operator: Precedence. (line 55) * / (forward slash), /= operator <1>: Precedence. (line 95) * / (forward slash), /= operator: Assignment Ops. (line 129) @@ -30109,17 +30200,18 @@ Index (line 147) * / (forward slash), patterns and: Expression Patterns. (line 24) * /= operator vs. /=.../ regexp constant: Assignment Ops. (line 147) -* /dev/... special files (gawk): Special FD. (line 46) -* /dev/fd/N special files: Special FD. (line 46) +* /dev/... special files: Special FD. (line 46) +* /dev/fd/N special files (gawk): Special FD. (line 46) * /inet/... special files (gawk): TCP/IP Networking. (line 6) * /inet4/... special files (gawk): TCP/IP Networking. (line 6) * /inet6/... special files (gawk): TCP/IP Networking. (line 6) -* ; (semicolon): Statements/Lines. (line 91) -* ; (semicolon), AWKPATH variable and: PC Using. (line 11) +* ; (semicolon), AWKPATH variable and: PC Using. (line 10) * ; (semicolon), separating statements in actions <1>: Statements. (line 10) -* ; (semicolon), separating statements in actions: Action Overview. +* ; (semicolon), separating statements in actions <2>: Action Overview. (line 19) +* ; (semicolon), separating statements in actions: Statements/Lines. + (line 91) * < (left angle bracket), < operator <1>: Precedence. (line 65) * < (left angle bracket), < operator: Comparison Operators. (line 11) @@ -30140,15 +30232,13 @@ Index (line 11) * > (right angle bracket), >> operator (I/O) <1>: Precedence. (line 65) * > (right angle bracket), >> operator (I/O): Redirection. (line 50) -* ? (question mark) regexp operator <1>: GNU Regexp Operators. - (line 59) -* ? (question mark) regexp operator: Regexp Operators. (line 111) * ? (question mark), ?: operator: Precedence. (line 92) -* [] (square brackets): Regexp Operators. (line 55) -* \ (backslash) <1>: Regexp Operators. (line 18) -* \ (backslash) <2>: Quoting. (line 31) -* \ (backslash) <3>: Comments. (line 50) -* \ (backslash): Read Terminal. (line 25) +* ? (question mark), regexp operator <1>: GNU Regexp Operators. + (line 59) +* ? (question mark), regexp operator: Regexp Operators. (line 111) +* [] (square brackets), regexp operator: Regexp Operators. (line 55) +* \ (backslash): Comments. (line 50) +* \ (backslash) in shell commands: Read Terminal. (line 25) * \ (backslash), \" escape sequence: Escape Sequences. (line 76) * \ (backslash), \' operator (gawk): GNU Regexp Operators. (line 56) @@ -30195,22 +30285,27 @@ Index * \ (backslash), in escape sequences, POSIX and: Escape Sequences. (line 112) * \ (backslash), in regexp constants: Computed Regexps. (line 28) -* ^ (caret): GNU Regexp Operators. - (line 59) +* \ (backslash), in shell commands: Quoting. (line 31) +* \ (backslash), regexp operator: Regexp Operators. (line 18) * ^ (caret), ^ operator: Precedence. (line 49) * ^ (caret), ^= operator <1>: Precedence. (line 95) * ^ (caret), ^= operator: Assignment Ops. (line 129) * ^ (caret), in bracket expressions: Bracket Expressions. (line 17) -* ^ (caret), regexp operator: Regexp Operators. (line 22) -* ^, in FS: Regexp Field Splitting. +* ^ (caret), in FS: Regexp Field Splitting. (line 59) +* ^ (caret), regexp operator <1>: GNU Regexp Operators. + (line 59) +* ^ (caret), regexp operator: Regexp Operators. (line 22) * _ (underscore), C macro: Explaining gettext. (line 70) * _ (underscore), in names of private variables: Library Names. (line 29) * _ (underscore), translatable string: Programmer i18n. (line 69) * _gr_init() user-defined function: Group Functions. (line 82) +* _ord_init() user-defined function: Ordinal Functions. (line 16) * _pw_init() user-defined function: Passwd Functions. (line 105) * accessing fields: Fields. (line 6) +* accessing global variables from extensions: Symbol Table Access. + (line 6) * account information <1>: Group Functions. (line 6) * account information: Passwd Functions. (line 16) * actions: Action Overview. (line 6) @@ -30222,8 +30317,6 @@ Index * adding, fields: Changing Fields. (line 53) * advanced features, fixed-width data: Constant Size. (line 10) * advanced features, gawk: Advanced Features. (line 6) -* advanced features, network connections, See Also networks, connections: Advanced Features. - (line 6) * advanced features, network programming: TCP/IP Networking. (line 6) * advanced features, nondecimal input data: Nondecimal Data. (line 6) * advanced features, processes, communicating with: Two-way I/O. @@ -30235,6 +30328,8 @@ Index * alarm clock example program: Alarm Program. (line 11) * alarm.awk program: Alarm Program. (line 31) * algorithms: Basic High Level. (line 68) +* allocating memory for extensions: Memory Allocation Functions. + (line 6) * Alpha (DEC): Manual History. (line 28) * amazing awk assembler (aaa): Glossary. (line 12) * amazingly workable formatter (awf): Glossary. (line 25) @@ -30245,17 +30340,25 @@ Index * ampersand (&), gsub()/gensub()/sub() functions and: Gory Details. (line 6) * anagram.awk program: Anagram Program. (line 22) +* anagrams, finding: Anagram Program. (line 6) +* and: Bitwise Functions. (line 39) * AND bitwise operation: Bitwise Functions. (line 6) * and Boolean-logic operator: Boolean Ops. (line 6) -* and() function (gawk): Bitwise Functions. (line 39) * ANSI: Glossary. (line 35) +* API informational variables: Extension API Informational Variables. + (line 6) +* API version: Extension Versioning. + (line 6) * arbitrary precision: Arbitrary Precision Arithmetic. (line 6) +* arbitrary precision integers: Arbitrary Precision Integers. + (line 6) * archeologists: Bugs. (line 6) -* ARGC/ARGV variables <1>: ARGC and ARGV. (line 6) +* arctangent: Numeric Functions. (line 11) * ARGC/ARGV variables: Auto-set. (line 11) * ARGC/ARGV variables, command-line arguments: Other Arguments. (line 12) +* ARGC/ARGV variables, how to use: ARGC and ARGV. (line 6) * ARGC/ARGV variables, portability and: Executable Scripts. (line 42) * ARGIND variable: Auto-set. (line 40) * ARGIND variable, command-line arguments: Other Arguments. (line 12) @@ -30265,53 +30368,69 @@ Index * arguments, command-line, invoking awk: Command Line. (line 6) * arguments, in function calls: Function Calls. (line 16) * arguments, processing: Getopt Function. (line 6) +* ARGV array, indexing into: Other Arguments. (line 12) * arithmetic operators: Arithmetic Ops. (line 6) +* array manipulation in extensions: Array Manipulation. (line 6) +* array members: Reference to Elements. + (line 6) +* array scanning order, controlling: Controlling Scanning. + (line 12) +* array, number of elements: String Functions. (line 194) * arrays: Arrays. (line 6) +* arrays of arrays: Arrays of Arrays. (line 6) +* arrays, an example of using: Array Example. (line 6) +* arrays, and IGNORECASE variable: Array Intro. (line 91) * arrays, as parameters to functions: Pass By Value/Reference. (line 47) * arrays, associative: Array Intro. (line 49) * arrays, associative, library functions and: Library Names. (line 57) * arrays, deleting entire contents: Delete. (line 39) -* arrays, elements, assigning: Assigning Elements. (line 6) +* arrays, elements that don't exist: Reference to Elements. + (line 23) +* arrays, elements, assigning values: Assigning Elements. (line 6) * arrays, elements, deleting: Delete. (line 6) -* arrays, elements, order of: Scanning an Array. (line 48) -* arrays, elements, referencing: Reference to Elements. - (line 6) +* arrays, elements, order of access by in operator: Scanning an Array. + (line 48) * arrays, elements, retrieving number of: String Functions. (line 32) * arrays, for statement and: Scanning an Array. (line 20) -* arrays, IGNORECASE variable and: Array Intro. (line 91) * arrays, indexing: Array Intro. (line 49) * arrays, merging into strings: Join Function. (line 6) * arrays, multidimensional: Multidimensional. (line 10) * arrays, multidimensional, scanning: Multiscanning. (line 11) -* arrays, names of: Arrays. (line 18) +* arrays, names of, and names of functions/variables: Arrays. (line 18) +* arrays, numeric subscripts: Numeric Array Subscripts. + (line 6) +* arrays, referencing elements: Reference to Elements. + (line 6) * arrays, scanning: Scanning an Array. (line 6) * arrays, sorting: Array Sorting Functions. (line 6) -* arrays, sorting, IGNORECASE variable and: Array Sorting Functions. +* arrays, sorting, and IGNORECASE variable: Array Sorting Functions. (line 83) * arrays, sparse: Array Intro. (line 70) -* arrays, subscripts: Numeric Array Subscripts. - (line 6) * arrays, subscripts, uninitialized variables as: Uninitialized Subscripts. (line 6) +* arrays, unassigned elements: Reference to Elements. + (line 18) * artificial intelligence, gawk and: Distribution contents. (line 52) -* ASCII <1>: Glossary. (line 141) +* ASCII <1>: Glossary. (line 133) * ASCII: Ordinal Functions. (line 45) -* asort() function (gawk) <1>: Array Sorting Functions. +* asort <1>: Array Sorting Functions. (line 6) -* asort() function (gawk): String Functions. (line 32) +* asort: String Functions. (line 32) * asort() function (gawk), arrays, sorting: Array Sorting Functions. (line 6) -* asorti() function (gawk) <1>: Array Sorting Functions. +* asorti <1>: Array Sorting Functions. (line 6) -* asorti() function (gawk): String Functions. (line 32) +* asorti: String Functions. (line 32) * asorti() function (gawk), arrays, sorting: Array Sorting Functions. (line 6) * assert() function (C library): Assert Function. (line 6) * assert() user-defined function: Assert Function. (line 28) * assertions: Assert Function. (line 6) +* assign values to variables, in debugger: Viewing And Changing Data. + (line 59) * assignment operators: Assignment Ops. (line 6) * assignment operators, evaluation order: Assignment Ops. (line 111) * assignment operators, lvalues/rvalues: Assignment Ops. (line 32) @@ -30329,7 +30448,8 @@ Index * asterisk (*), **= operator: Assignment Ops. (line 129) * asterisk (*), *= operator <1>: Precedence. (line 95) * asterisk (*), *= operator: Assignment Ops. (line 129) -* atan2() function: Numeric Functions. (line 11) +* atan2: Numeric Functions. (line 11) +* automatic displays, in debugger: Debugger Info. (line 24) * awf (amazingly workable formatter) program: Glossary. (line 25) * awk debugging, enabling: Options. (line 108) * awk language, POSIX version: Assignment Ops. (line 136) @@ -30385,16 +30505,14 @@ Index * awk, versions of, See Also Brian Kernighan's awk: BTL. (line 6) * awka compiler for awk: Other Versions. (line 64) * AWKLIBPATH environment variable: AWKLIBPATH Variable. (line 6) -* AWKPATH environment variable <1>: PC Using. (line 11) +* AWKPATH environment variable <1>: PC Using. (line 10) * AWKPATH environment variable: AWKPATH Variable. (line 6) * awkprof.out file: Profiling. (line 6) * awksed.awk program: Simple Sed. (line 25) * awkvars.out file: Options. (line 93) * b debugger command (alias for break): Breakpoint Control. (line 11) -* backslash (\) <1>: Regexp Operators. (line 18) -* backslash (\) <2>: Quoting. (line 31) -* backslash (\) <3>: Comments. (line 50) -* backslash (\): Read Terminal. (line 25) +* backslash (\): Comments. (line 50) +* backslash (\) in shell commands: Read Terminal. (line 25) * backslash (\), \" escape sequence: Escape Sequences. (line 76) * backslash (\), \' operator (gawk): GNU Regexp Operators. (line 56) @@ -30441,17 +30559,18 @@ Index * backslash (\), in escape sequences, POSIX and: Escape Sequences. (line 112) * backslash (\), in regexp constants: Computed Regexps. (line 28) +* backslash (\), in shell commands: Quoting. (line 31) +* backslash (\), regexp operator: Regexp Operators. (line 18) * backtrace debugger command: Execution Stack. (line 13) -* BBS-list file: Sample Data Files. (line 6) -* Beebe, Nelson <1>: Other Versions. (line 78) -* Beebe, Nelson: Acknowledgments. (line 60) -* BEGIN pattern <1>: Profiling. (line 62) +* Beebe, Nelson H.F. <1>: Other Versions. (line 78) +* Beebe, Nelson H.F.: Acknowledgments. (line 60) +* BEGIN pattern <1>: Using BEGIN/END. (line 6) * BEGIN pattern <2>: BEGIN/END. (line 6) -* BEGIN pattern <3>: Field Separators. (line 45) -* BEGIN pattern: Records. (line 29) +* BEGIN pattern: Field Separators. (line 45) +* BEGIN pattern, and profiling: Profiling. (line 62) * BEGIN pattern, assert() user-defined function and: Assert Function. (line 83) -* BEGIN pattern, Boolean patterns and: Expression Patterns. (line 73) +* BEGIN pattern, Boolean patterns and: Expression Patterns. (line 70) * BEGIN pattern, exit statement and: Exit Statement. (line 12) * BEGIN pattern, getline and: Getline Notes. (line 19) * BEGIN pattern, headings, adding: Print Examples. (line 43) @@ -30468,29 +30587,36 @@ Index * BEGIN pattern, TEXTDOMAIN variable and: Programmer i18n. (line 60) * BEGINFILE pattern: BEGINFILE/ENDFILE. (line 6) * BEGINFILE pattern, Boolean patterns and: Expression Patterns. - (line 73) + (line 70) * beginfile() user-defined function: Filetrans Function. (line 62) +* Bentley, Jon: Glossary. (line 143) * Benzinger, Michael: Contributors. (line 97) +* Berry, Karl <1>: Ranges and Locales. (line 74) * Berry, Karl: Acknowledgments. (line 33) * binary input/output: User-modified. (line 10) +* bindtextdomain <1>: Programmer i18n. (line 47) +* bindtextdomain: I18N Functions. (line 12) * bindtextdomain() function (C library): Explaining gettext. (line 49) -* bindtextdomain() function (gawk) <1>: Programmer i18n. (line 47) -* bindtextdomain() function (gawk): I18N Functions. (line 12) * bindtextdomain() function (gawk), portability and: I18N Portability. (line 33) -* BINMODE variable <1>: PC Using. (line 34) +* BINMODE variable <1>: PC Using. (line 33) * BINMODE variable: User-modified. (line 10) +* bit-manipulation functions: Bitwise Functions. (line 6) * bits2str() user-defined function: Bitwise Functions. (line 70) +* bitwise AND: Bitwise Functions. (line 39) +* bitwise complement: Bitwise Functions. (line 43) +* bitwise OR: Bitwise Functions. (line 49) +* bitwise XOR: Bitwise Functions. (line 55) * bitwise, complement: Bitwise Functions. (line 25) * bitwise, operations: Bitwise Functions. (line 6) * bitwise, shift: Bitwise Functions. (line 32) * body, in actions: Statements. (line 10) * body, in loops: While Statement. (line 14) * Boolean expressions: Boolean Ops. (line 6) -* Boolean expressions, as patterns: Expression Patterns. (line 41) +* Boolean expressions, as patterns: Expression Patterns. (line 39) * Boolean operators, See Boolean expressions: Boolean Ops. (line 6) * Bourne shell, quoting rules for: Quoting. (line 18) -* braces ({}): Profiling. (line 134) +* braces ({}): Profiling. (line 142) * braces ({}), actions and: Action Overview. (line 19) * braces ({}), statements, grouping: Statements. (line 10) * bracket expressions <1>: Bracket Expressions. (line 6) @@ -30509,17 +30635,44 @@ Index (line 6) * break debugger command: Breakpoint Control. (line 11) * break statement: Break Statement. (line 6) +* breakpoint: Debugging Terms. (line 33) +* breakpoint at location, how to delete: Breakpoint Control. (line 36) +* breakpoint commands: Debugger Execution Control. + (line 10) +* breakpoint condition: Breakpoint Control. (line 54) +* breakpoint, delete by number: Breakpoint Control. (line 64) +* breakpoint, how to disable or enable: Breakpoint Control. (line 69) +* breakpoint, setting: Breakpoint Control. (line 11) * Brennan, Michael <1>: Other Versions. (line 6) * Brennan, Michael <2>: Two-way I/O. (line 6) * Brennan, Michael <3>: Simple Sed. (line 25) -* Brennan, Michael: Delete. (line 56) -* Brian Kernighan's awk: Other Versions. (line 13) +* Brennan, Michael <4>: Delete. (line 56) +* Brennan, Michael: Foreword. (line 83) +* Brian Kernighan's awk <1>: I/O Functions. (line 40) +* Brian Kernighan's awk <2>: Gory Details. (line 15) +* Brian Kernighan's awk <3>: String Functions. (line 490) +* Brian Kernighan's awk <4>: Delete. (line 48) +* Brian Kernighan's awk <5>: Nextfile Statement. (line 47) +* Brian Kernighan's awk <6>: Continue Statement. (line 43) +* Brian Kernighan's awk <7>: Break Statement. (line 51) +* Brian Kernighan's awk <8>: I/O And BEGIN/END. (line 16) +* Brian Kernighan's awk <9>: Concatenation. (line 36) +* Brian Kernighan's awk <10>: Getline/Pipe. (line 62) +* Brian Kernighan's awk <11>: Regexp Field Splitting. + (line 67) +* Brian Kernighan's awk <12>: GNU Regexp Operators. + (line 83) +* Brian Kernighan's awk <13>: Escape Sequences. (line 116) +* Brian Kernighan's awk <14>: When. (line 21) +* Brian Kernighan's awk: Preface. (line 15) * Brian Kernighan's awk, extensions: BTL. (line 6) +* Brian Kernighan's awk, source code: Other Versions. (line 13) +* Brini, Davide: Signature Program. (line 6) * Broder, Alan J.: Contributors. (line 88) * Brown, Martin: Contributors. (line 82) -* BSD-based operating systems: Glossary. (line 624) +* BSD-based operating systems: Glossary. (line 616) * bt debugger command (alias for backtrace): Execution Stack. (line 13) -* Buening, Andreas <1>: Bugs. (line 71) +* Buening, Andreas <1>: Bugs. (line 70) * Buening, Andreas <2>: Contributors. (line 92) * Buening, Andreas: Acknowledgments. (line 60) * buffering, input/output <1>: Two-way I/O. (line 70) @@ -30541,24 +30694,29 @@ Index (line 47) * call by value: Pass By Value/Reference. (line 18) -* caret (^): GNU Regexp Operators. - (line 59) +* call stack, display in debugger: Execution Stack. (line 13) * caret (^), ^ operator: Precedence. (line 49) * caret (^), ^= operator <1>: Precedence. (line 95) * caret (^), ^= operator: Assignment Ops. (line 129) * caret (^), in bracket expressions: Bracket Expressions. (line 17) +* caret (^), regexp operator <1>: GNU Regexp Operators. + (line 59) * caret (^), regexp operator: Regexp Operators. (line 22) * case keyword: Switch Statement. (line 6) +* case sensitivity, and regexps: User-modified. (line 82) +* case sensitivity, and string comparisons: User-modified. (line 82) * case sensitivity, array indices and: Array Intro. (line 91) -* case sensitivity, converting case: String Functions. (line 519) +* case sensitivity, converting case: String Functions. (line 520) * case sensitivity, example programs: Library Functions. (line 53) * case sensitivity, gawk: Case-sensitivity. (line 26) -* case sensitivity, regexps and <1>: User-modified. (line 82) * case sensitivity, regexps and: Case-sensitivity. (line 6) -* case sensitivity, string comparisons and: User-modified. (line 82) * CGI, awk scripts for: Options. (line 125) +* changing precision of a number: Changing Precision. (line 6) +* character classes, See bracket expressions: Regexp Operators. + (line 55) +* character lists in regular expression: Bracket Expressions. (line 6) * character lists, See bracket expressions: Regexp Operators. (line 55) -* character sets (machine character encodings) <1>: Glossary. (line 141) +* character sets (machine character encodings) <1>: Glossary. (line 133) * character sets (machine character encodings): Ordinal Functions. (line 45) * character sets, See Also bracket expressions: Regexp Operators. @@ -30569,7 +30727,7 @@ Index * Chassell, Robert J.: Acknowledgments. (line 33) * chdir() extension function: Extension Sample File Functions. (line 12) -* chem utility: Glossary. (line 151) +* chem utility: Glossary. (line 143) * chr() extension function: Extension Sample Ord. (line 15) * chr() user-defined function: Ordinal Functions. (line 16) @@ -30578,12 +30736,12 @@ Index (line 6) * cliff_rand() user-defined function: Cliff Random Function. (line 12) -* close() function <1>: I/O Functions. (line 10) -* close() function <2>: Close Files And Pipes. +* close <1>: I/O Functions. (line 10) +* close: Close Files And Pipes. (line 18) -* close() function <3>: Getline/Pipe. (line 27) -* close() function: Getline/Variable/File. - (line 30) +* close file or coprocess: I/O Functions. (line 10) +* close() function, portability: Close Files And Pipes. + (line 81) * close() function, return value: Close Files And Pipes. (line 130) * close() function, two-way pipes and: Two-way I/O. (line 77) @@ -30592,10 +30750,12 @@ Index * Collado, Manuel: Acknowledgments. (line 60) * collating elements: Bracket Expressions. (line 69) * collating symbols: Bracket Expressions. (line 76) +* Colombo, Antonio <1>: Contributors. (line 135) * Colombo, Antonio: Acknowledgments. (line 60) * columns, aligning: Print Examples. (line 70) * columns, cutting: Cut Program. (line 6) * comma (,), in range patterns: Ranges. (line 6) +* command completion, in debugger: Readline Support. (line 6) * command line, arguments <1>: ARGC and ARGV. (line 6) * command line, arguments <2>: Auto-set. (line 11) * command line, arguments: Other Arguments. (line 6) @@ -30605,16 +30765,16 @@ Index * command line, FS on, setting: Command Line Field Separator. (line 6) * command line, invoking awk from: Command Line. (line 6) -* command line, options <1>: Command Line Field Separator. - (line 6) -* command line, options <2>: Options. (line 6) -* command line, options: Long. (line 12) +* command line, option -f: Long. (line 12) +* command line, options: Options. (line 6) * command line, options, end of: Options. (line 54) * command line, variables, assigning on: Assignment Options. (line 6) * command-line options, processing: Getopt Function. (line 6) * command-line options, string extraction: String Extraction. (line 6) * commands debugger command: Debugger Execution Control. (line 10) +* commands to execute at breakpoint: Debugger Execution Control. + (line 10) * commenting: Comments. (line 6) * commenting, backslash continuation and: Statements/Lines. (line 76) * common extensions, ** operator: Arithmetic Ops. (line 30) @@ -30623,12 +30783,12 @@ Index * common extensions, /dev/stdin special file: Special FD. (line 46) * common extensions, /dev/stdout special file: Special FD. (line 46) * common extensions, \x escape sequence: Escape Sequences. (line 61) -* common extensions, BINMODE variable: PC Using. (line 34) +* common extensions, BINMODE variable: PC Using. (line 33) * common extensions, delete to delete entire arrays: Delete. (line 39) * common extensions, func keyword: Definition Syntax. (line 83) * common extensions, length() applied to an array: String Functions. - (line 193) -* common extensions, RS as a regexp: Records. (line 120) + (line 194) +* common extensions, RS as a regexp: Records. (line 135) * common extensions, single character fields: Single Character Fields. (line 6) * comp.lang.awk newsgroup: Bugs. (line 38) @@ -30644,13 +30804,13 @@ Index * compatibility mode (gawk), octal numbers: Nondecimal-numbers. (line 60) * compatibility mode (gawk), specifying: Options. (line 81) -* compiled programs <1>: Glossary. (line 165) +* compiled programs <1>: Glossary. (line 157) * compiled programs: Basic High Level. (line 15) * compiling gawk for Cygwin: Cygwin. (line 6) * compiling gawk for MS-DOS and MS-Windows: PC Compiling. (line 13) * compiling gawk for VMS: VMS Compilation. (line 6) * compiling gawk with EMX for OS/2: PC Compiling. (line 28) -* compl() function (gawk): Bitwise Functions. (line 43) +* compl: Bitwise Functions. (line 43) * complement, bitwise: Bitwise Functions. (line 25) * compound statements, control statements and: Statements. (line 10) * concatenating: Concatenation. (line 8) @@ -30666,46 +30826,59 @@ Index (line 35) * configuration options, gawk: Additional Configuration Options. (line 6) +* constant regexps: Regexp Usage. (line 57) * constants, floating-point: Floating-point Constants. (line 6) * constants, nondecimal: Nondecimal Data. (line 6) +* constants, numeric: Scalar Constants. (line 6) * constants, types of: Constants. (line 6) * context, floating-point: Floating-point Context. (line 6) +* continue program, in debugger: Debugger Execution Control. + (line 33) * continue statement: Continue Statement. (line 6) * control statements: Statements. (line 6) -* converting, case: String Functions. (line 519) -* converting, dates to timestamps: Time Functions. (line 75) -* converting, during subscripting: Numeric Array Subscripts. +* controlling array scanning order: Controlling Scanning. + (line 12) +* convert string to lower case: String Functions. (line 521) +* convert string to number: String Functions. (line 385) +* convert string to upper case: String Functions. (line 527) +* converting integer array subscripts: Numeric Array Subscripts. (line 31) +* converting, dates to timestamps: Time Functions. (line 76) * converting, numbers to strings <1>: Bitwise Functions. (line 109) * converting, numbers to strings: Conversion. (line 6) * converting, strings to numbers <1>: Bitwise Functions. (line 109) * converting, strings to numbers: Conversion. (line 6) * CONVFMT variable <1>: User-modified. (line 28) * CONVFMT variable: Conversion. (line 29) -* CONVFMT variable, array subscripts and: Numeric Array Subscripts. +* CONVFMT variable, and array subscripts: Numeric Array Subscripts. (line 6) -* cookie: Glossary. (line 157) +* cookie: Glossary. (line 149) * coprocesses <1>: Two-way I/O. (line 44) * coprocesses: Redirection. (line 102) * coprocesses, closing: Close Files And Pipes. (line 6) * coprocesses, getline from: Getline/Coprocess. (line 6) -* cos() function: Numeric Functions. (line 15) +* cos: Numeric Functions. (line 15) +* cosine: Numeric Functions. (line 15) * counting: Wc Program. (line 6) * csh utility: Statements/Lines. (line 44) * csh utility, POSIXLY_CORRECT environment variable: Options. (line 348) * csh utility, |& operator, comparison with: Two-way I/O. (line 44) -* ctime() user-defined function: Function Example. (line 72) +* ctime() user-defined function: Function Example. (line 73) * currency symbols, localization: Explaining gettext. (line 103) +* current system time: Time Functions. (line 66) * custom.h file: Configuration Philosophy. (line 30) +* customized input parser: Input Parsers. (line 6) +* customized output wrapper: Output Wrappers. (line 6) +* customized two-way processor: Two-way processors. (line 6) * cut utility: Cut Program. (line 6) * cut.awk program: Cut Program. (line 45) * d debugger command (alias for delete): Breakpoint Control. (line 64) * d.c., See dark corner: Conventions. (line 38) -* dark corner <1>: Glossary. (line 197) +* dark corner <1>: Glossary. (line 189) * dark corner: Conventions. (line 38) * dark corner, "0" is actually true: Truth Values. (line 24) * dark corner, /= operator vs. /=.../ regexp constant: Assignment Ops. @@ -30732,9 +30905,9 @@ Index * dark corner, format-control characters: Control Letters. (line 18) * dark corner, FS as null string: Single Character Fields. (line 20) -* dark corner, input files: Records. (line 103) +* dark corner, input files: Records. (line 118) * dark corner, invoking awk: Command Line. (line 16) -* dark corner, length() function: String Functions. (line 179) +* dark corner, length() function: String Functions. (line 180) * dark corner, locale's decimal point character: Conversion. (line 77) * dark corner, multiline records: Multiple Line. (line 35) * dark corner, NF variable, decrementing: Changing Fields. (line 107) @@ -30745,26 +30918,26 @@ Index (line 147) * dark corner, regexp constants, as arguments to user-defined functions: Using Constant Regexps. (line 43) -* dark corner, split() function: String Functions. (line 358) -* dark corner, strings, storing: Records. (line 195) +* dark corner, split() function: String Functions. (line 359) +* dark corner, strings, storing: Records. (line 210) * dark corner, value of ARGV[0]: Auto-set. (line 35) * data, fixed-width: Constant Size. (line 10) * data-driven languages: Basic High Level. (line 85) * database, group, reading: Group Functions. (line 6) * database, users, reading: Passwd Functions. (line 6) * date utility, GNU: Time Functions. (line 17) -* date utility, POSIX: Time Functions. (line 262) -* dates, converting to timestamps: Time Functions. (line 75) +* date utility, POSIX: Time Functions. (line 263) +* dates, converting to timestamps: Time Functions. (line 76) * dates, information related to, localization: Explaining gettext. (line 115) * Davies, Stephen <1>: Contributors. (line 74) * Davies, Stephen: Acknowledgments. (line 60) -* dcgettext() function (gawk) <1>: Programmer i18n. (line 19) -* dcgettext() function (gawk): I18N Functions. (line 22) +* dcgettext <1>: Programmer i18n. (line 19) +* dcgettext: I18N Functions. (line 22) * dcgettext() function (gawk), portability and: I18N Portability. (line 33) -* dcngettext() function (gawk) <1>: Programmer i18n. (line 36) -* dcngettext() function (gawk): I18N Functions. (line 28) +* dcngettext <1>: Programmer i18n. (line 36) +* dcngettext: I18N Functions. (line 28) * dcngettext() function (gawk), portability and: I18N Portability. (line 33) * deadlocks: Two-way I/O. (line 70) @@ -30864,6 +31037,13 @@ Index (line 67) * debugger commands, watch: Viewing And Changing Data. (line 67) +* debugger default list amount: Debugger Info. (line 69) +* debugger history file: Debugger Info. (line 80) +* debugger history size: Debugger Info. (line 65) +* debugger options: Debugger Info. (line 57) +* debugger prompt: Debugger Info. (line 77) +* debugger, how to start: Debugger Invocation. (line 6) +* debugger, read commands from a file: Debugger Info. (line 96) * debugging awk programs: Debugger. (line 6) * debugging gawk, bug reports: Bugs. (line 9) * decimal point character, locale specific: Options. (line 263) @@ -30872,12 +31052,18 @@ Index * Deifik, Scott <1>: Bugs. (line 70) * Deifik, Scott <2>: Contributors. (line 53) * Deifik, Scott: Acknowledgments. (line 60) +* delete ARRAY: Delete. (line 39) +* delete breakpoint at location: Breakpoint Control. (line 36) +* delete breakpoint by number: Breakpoint Control. (line 64) * delete debugger command: Breakpoint Control. (line 64) * delete statement: Delete. (line 6) +* delete watchpoint: Viewing And Changing Data. + (line 84) * deleting elements in arrays: Delete. (line 6) * deleting entire arrays: Delete. (line 39) * Demaille, Akim: Acknowledgments. (line 60) -* differences between gawk and awk: String Functions. (line 193) +* describe call stack frame, in debugger: Debugger Info. (line 27) +* differences between gawk and awk: String Functions. (line 194) * differences in awk and gawk, ARGC/ARGV variables: ARGC and ARGV. (line 88) * differences in awk and gawk, ARGIND variable: Auto-set. (line 40) @@ -30892,11 +31078,13 @@ Index * differences in awk and gawk, BEGINFILE/ENDFILE patterns: BEGINFILE/ENDFILE. (line 6) * differences in awk and gawk, BINMODE variable <1>: PC Using. - (line 34) + (line 33) * differences in awk and gawk, BINMODE variable: User-modified. (line 23) * differences in awk and gawk, close() function: Close Files And Pipes. (line 81) +* differences in awk and gawk, command line directories: Command line directories. + (line 6) * differences in awk and gawk, ERRNO variable: Auto-set. (line 82) * differences in awk and gawk, error messages: Special FD. (line 16) * differences in awk and gawk, FIELDWIDTHS variable: User-modified. @@ -30922,25 +31110,23 @@ Index (line 34) * differences in awk and gawk, LINT variable: User-modified. (line 98) * differences in awk and gawk, match() function: String Functions. - (line 256) + (line 257) * differences in awk and gawk, print/printf statements: Format Modifiers. (line 13) * differences in awk and gawk, PROCINFO array: Auto-set. (line 142) -* differences in awk and gawk, record separators: Records. (line 117) +* differences in awk and gawk, record separators: Records. (line 132) * differences in awk and gawk, regexp constants: Using Constant Regexps. (line 43) * differences in awk and gawk, regular expressions: Case-sensitivity. (line 26) -* differences in awk and gawk, RS/RT variables: Records. (line 172) +* differences in awk and gawk, RS/RT variables: Records. (line 187) * differences in awk and gawk, RT variable: Auto-set. (line 275) * differences in awk and gawk, single-character fields: Single Character Fields. (line 6) * differences in awk and gawk, split() function: String Functions. - (line 346) + (line 347) * differences in awk and gawk, strings: Scalar Constants. (line 20) -* differences in awk and gawk, strings, storing: Records. (line 191) -* differences in awk and gawk, strtonum() function (gawk): String Functions. - (line 401) +* differences in awk and gawk, strings, storing: Records. (line 206) * differences in awk and gawk, SYMTAB variable: Auto-set. (line 283) * differences in awk and gawk, TEXTDOMAIN variable: User-modified. (line 162) @@ -30948,57 +31134,71 @@ Index (line 66) * directories, command line: Command line directories. (line 6) -* directories, searching <1>: Igawk Program. (line 368) -* directories, searching <2>: AWKLIBPATH Variable. (line 6) -* directories, searching: AWKPATH Variable. (line 6) +* directories, searching: Igawk Program. (line 368) +* directories, searching for shared libraries: AWKLIBPATH Variable. + (line 6) +* directories, searching for source files: AWKPATH Variable. (line 6) +* disable breakpoint: Breakpoint Control. (line 69) * disable debugger command: Breakpoint Control. (line 69) * display debugger command: Viewing And Changing Data. (line 8) +* display debugger options: Debugger Info. (line 57) * division: Arithmetic Ops. (line 44) -* do-while statement <1>: Do Statement. (line 6) -* do-while statement: Regexp Usage. (line 19) +* do-while statement: Do Statement. (line 6) +* do-while statement, use of regexps in: Regexp Usage. (line 19) * documentation, of awk programs: Library Names. (line 6) * documentation, online: Manual History. (line 11) * documents, searching: Dupword Program. (line 6) -* dollar sign ($): Regexp Operators. (line 35) * dollar sign ($), $ field operator <1>: Precedence. (line 43) * dollar sign ($), $ field operator: Fields. (line 19) * dollar sign ($), incrementing fields and arrays: Increment Ops. (line 30) +* dollar sign ($), regexp operator: Regexp Operators. (line 35) * double precision floating-point: General Arithmetic. (line 21) -* double quote (") <1>: Quoting. (line 37) -* double quote ("): Read Terminal. (line 25) +* double quote (") in shell commands: Read Terminal. (line 25) * double quote ("), in regexp constants: Computed Regexps. (line 28) +* double quote ("), in shell commands: Quoting. (line 37) * down debugger command: Execution Stack. (line 21) * Drepper, Ulrich: Acknowledgments. (line 52) +* dump all variables of a program: Options. (line 93) * dump debugger command: Miscellaneous Debugger Commands. (line 9) * dupword.awk program: Dupword Program. (line 31) +* dynamic profiling: Profiling. (line 179) +* dynamically loaded extensions: Dynamic Extensions. (line 6) * e debugger command (alias for enable): Breakpoint Control. (line 73) * EBCDIC: Ordinal Functions. (line 45) +* effective group ID of gawk user: Auto-set. (line 147) +* effective user ID of gawk user: Auto-set. (line 151) * egrep utility <1>: Egrep Program. (line 6) * egrep utility: Bracket Expressions. (line 24) * egrep.awk program: Egrep Program. (line 54) -* elements in arrays: Reference to Elements. - (line 6) -* elements in arrays, assigning: Assigning Elements. (line 6) +* elements in arrays, assigning values: Assigning Elements. (line 6) * elements in arrays, deleting: Delete. (line 6) -* elements in arrays, order of: Scanning an Array. (line 48) +* elements in arrays, order of access by in operator: Scanning an Array. + (line 48) * elements in arrays, scanning: Scanning an Array. (line 6) +* elements of arrays: Reference to Elements. + (line 6) * email address for bug reports, bug-gawk@gnu.org: Bugs. (line 30) * EMISTERED: TCP/IP Networking. (line 6) +* empty array elements: Reference to Elements. + (line 18) * empty pattern: Empty. (line 6) +* empty strings: Records. (line 122) * empty strings, See null strings: Regexp Field Splitting. (line 43) +* enable breakpoint: Breakpoint Control. (line 73) * enable debugger command: Breakpoint Control. (line 73) * end debugger command: Debugger Execution Control. (line 10) -* END pattern <1>: Profiling. (line 62) +* END pattern <1>: Using BEGIN/END. (line 6) * END pattern: BEGIN/END. (line 6) +* END pattern, and profiling: Profiling. (line 62) * END pattern, assert() user-defined function and: Assert Function. (line 75) * END pattern, backslash continuation and: Egrep Program. (line 220) -* END pattern, Boolean patterns and: Expression Patterns. (line 73) +* END pattern, Boolean patterns and: Expression Patterns. (line 70) * END pattern, exit statement and: Exit Statement. (line 12) * END pattern, next/nextfile statements and <1>: Next Statement. (line 45) @@ -31007,34 +31207,38 @@ Index * END pattern, operators and: Using BEGIN/END. (line 17) * END pattern, print statement and: I/O And BEGIN/END. (line 16) * ENDFILE pattern: BEGINFILE/ENDFILE. (line 6) -* ENDFILE pattern, Boolean patterns and: Expression Patterns. (line 73) +* ENDFILE pattern, Boolean patterns and: Expression Patterns. (line 70) * endfile() user-defined function: Filetrans Function. (line 62) * endgrent() function (C library): Group Functions. (line 215) * endgrent() user-defined function: Group Functions. (line 218) * endpwent() function (C library): Passwd Functions. (line 210) * endpwent() user-defined function: Passwd Functions. (line 213) * ENVIRON array: Auto-set. (line 60) -* environment variables: Auto-set. (line 60) -* epoch, definition of: Glossary. (line 243) +* environment variables used by gawk: Environment Variables. + (line 6) +* environment variables, in ENVIRON array: Auto-set. (line 60) +* epoch, definition of: Glossary. (line 235) * equals sign (=), = operator: Assignment Ops. (line 6) * equals sign (=), == operator <1>: Precedence. (line 65) * equals sign (=), == operator: Comparison Operators. (line 11) * EREs (Extended Regular Expressions): Bracket Expressions. (line 24) * ERRNO variable <1>: TCP/IP Networking. (line 54) -* ERRNO variable <2>: Auto-set. (line 82) -* ERRNO variable <3>: BEGINFILE/ENDFILE. (line 26) -* ERRNO variable <4>: Close Files And Pipes. +* ERRNO variable: Auto-set. (line 82) +* ERRNO variable, with BEGINFILE pattern: BEGINFILE/ENDFILE. (line 26) +* ERRNO variable, with close() function: Close Files And Pipes. (line 138) -* ERRNO variable: Getline. (line 19) +* ERRNO variable, with getline command: Getline. (line 19) * error handling: Special FD. (line 16) * error handling, ERRNO variable and: Auto-set. (line 82) * error output: Special FD. (line 6) * escape processing, gsub()/gensub()/sub() functions: Gory Details. (line 6) -* escape sequences: Escape Sequences. (line 6) +* escape sequences, in strings: Escape Sequences. (line 6) * eval debugger command: Viewing And Changing Data. (line 23) +* evaluate expressions, in debugger: Viewing And Changing Data. + (line 23) * evaluation order: Increment Ops. (line 60) * evaluation order, concatenation: Concatenation. (line 41) * evaluation order, functions: Calling Built-in. (line 30) @@ -31057,9 +31261,12 @@ Index * exit statement: Exit Statement. (line 6) * exit status, of gawk: Exit Status. (line 6) * exit status, of VMS: VMS Running. (line 29) -* exp() function: Numeric Functions. (line 18) +* exit the debugger: Miscellaneous Debugger Commands. + (line 99) +* exp: Numeric Functions. (line 18) * expand utility: Very Simple. (line 69) * Expat XML parser library: gawkextlib. (line 35) +* exponent: Numeric Functions. (line 18) * expressions: Expressions. (line 6) * expressions, as patterns: Expression Patterns. (line 6) * expressions, assignment: Assignment Ops. (line 6) @@ -31071,6 +31278,20 @@ Index (line 9) * expressions, selecting: Conditional Exp. (line 6) * Extended Regular Expressions (EREs): Bracket Expressions. (line 24) +* extension API: Extension API Description. + (line 6) +* extension API informational variables: Extension API Informational Variables. + (line 6) +* extension API version: Extension Versioning. + (line 6) +* extension API, version number: Auto-set. (line 238) +* extension example: Extension Example. (line 6) +* extension registration: Registration Functions. + (line 6) +* extension search path: Finding Extensions. (line 6) +* extensions distributed with gawk: Extension Samples. (line 6) +* extensions, allocating memory: Memory Allocation Functions. + (line 6) * extensions, Brian Kernighan's awk <1>: Common Extensions. (line 6) * extensions, Brian Kernighan's awk: BTL. (line 6) * extensions, common, ** operator: Arithmetic Ops. (line 30) @@ -31079,43 +31300,45 @@ Index * extensions, common, /dev/stdin special file: Special FD. (line 46) * extensions, common, /dev/stdout special file: Special FD. (line 46) * extensions, common, \x escape sequence: Escape Sequences. (line 61) -* extensions, common, BINMODE variable: PC Using. (line 34) +* extensions, common, BINMODE variable: PC Using. (line 33) * extensions, common, delete to delete entire arrays: Delete. (line 39) +* extensions, common, fflush() function: I/O Functions. (line 40) * extensions, common, func keyword: Definition Syntax. (line 83) * extensions, common, length() applied to an array: String Functions. - (line 193) -* extensions, common, RS as a regexp: Records. (line 120) + (line 194) +* extensions, common, RS as a regexp: Records. (line 135) * extensions, common, single character fields: Single Character Fields. (line 6) * extensions, in gawk, not in POSIX awk: POSIX/GNU. (line 6) * extensions, mawk: Common Extensions. (line 6) +* extensions, where to find: gawkextlib. (line 6) * extract.awk program: Extract Program. (line 79) * extraction, of marked strings (internationalization): String Extraction. (line 6) * f debugger command (alias for frame): Execution Stack. (line 25) * false, logical: Truth Values. (line 6) * FDL (Free Documentation License): GNU Free Documentation License. - (line 6) + (line 7) * features, adding to gawk: Adding Code. (line 6) * features, advanced, See advanced features: Obsolete. (line 6) * features, deprecated: Obsolete. (line 6) * features, undocumented: Undocumented. (line 6) * Fenlason, Jay <1>: Contributors. (line 18) * Fenlason, Jay: History. (line 30) -* fflush() function: I/O Functions. (line 25) +* fflush: I/O Functions. (line 25) * field numbers: Nonconstant Fields. (line 6) * field operator $: Fields. (line 19) * field operators, dollar sign as: Fields. (line 19) +* field separator, in multiline records: Multiple Line. (line 41) +* field separator, on command line: Command Line Field Separator. + (line 6) +* field separator, POSIX and: Field Splitting Summary. + (line 40) * field separators <1>: User-modified. (line 56) * field separators: Field Separators. (line 15) * field separators, choice of: Field Separators. (line 51) * field separators, FIELDWIDTHS variable and: User-modified. (line 35) * field separators, FPAT variable and: User-modified. (line 45) -* field separators, in multiline records: Multiple Line. (line 41) -* field separators, on command line: Command Line Field Separator. - (line 6) -* field separators, POSIX and <1>: Field Splitting Summary. - (line 40) * field separators, POSIX and: Fields. (line 6) * field separators, regular expressions as <1>: Regexp Field Splitting. (line 6) @@ -31157,7 +31380,6 @@ Index * files, /inet/... (gawk): TCP/IP Networking. (line 6) * files, /inet4/... (gawk): TCP/IP Networking. (line 6) * files, /inet6/... (gawk): TCP/IP Networking. (line 6) -* files, as single records: Records. (line 204) * files, awk programs in: Long. (line 6) * files, awkprof.out: Profiling. (line 6) * files, awkvars.out: Options. (line 93) @@ -31196,19 +31418,22 @@ Index * files, source, search path for: Igawk Program. (line 368) * files, splitting: Split Program. (line 6) * files, Texinfo, extracting programs from: Extract Program. (line 6) +* find substring in string: String Functions. (line 151) +* finding extensions: Finding Extensions. (line 6) * finish debugger command: Debugger Execution Control. (line 39) * Fish, Fred: Contributors. (line 50) * fixed-width data: Constant Size. (line 10) * flag variables <1>: Tee Program. (line 20) * flag variables: Boolean Ops. (line 67) -* floating-point numbers, arbitrary precision: Arbitrary Precision Arithmetic. - (line 6) * floating-point, numbers <1>: Unexpected Results. (line 6) * floating-point, numbers: General Arithmetic. (line 6) +* floating-point, numbers, arbitrary precision: Arbitrary Precision Arithmetic. + (line 6) * floating-point, VAX/VMS: VMS Running. (line 51) +* flush buffered output: I/O Functions. (line 25) * fnmatch() extension function: Extension Sample Fnmatch. - (line 6) + (line 12) * FNR variable <1>: Auto-set. (line 112) * FNR variable: Records. (line 6) * FNR variable, changing: Auto-set. (line 323) @@ -31216,15 +31441,17 @@ Index * for statement, looping over arrays: Scanning an Array. (line 20) * fork() extension function: Extension Sample Fork. (line 11) +* format specifiers: Basic Printf. (line 15) * format specifiers, mixing regular with positional specifiers: Printf Ordering. (line 57) * format specifiers, printf statement: Control Letters. (line 6) * format specifiers, strftime() function (gawk): Time Functions. - (line 88) -* format strings: Basic Printf. (line 15) + (line 89) +* format time string: Time Functions. (line 48) * formats, numeric output: OFMT. (line 6) * formatting output: Printf. (line 6) -* forward slash (/): Regexp. (line 10) +* formatting strings: String Functions. (line 378) +* forward slash (/) to enclose regular expressions: Regexp. (line 10) * forward slash (/), / operator: Precedence. (line 55) * forward slash (/), /= operator <1>: Precedence. (line 95) * forward slash (/), /= operator: Assignment Ops. (line 129) @@ -31236,11 +31463,11 @@ Index (line 27) * frame debugger command: Execution Stack. (line 25) * Free Documentation License (FDL): GNU Free Documentation License. - (line 6) -* Free Software Foundation (FSF) <1>: Glossary. (line 305) + (line 7) +* Free Software Foundation (FSF) <1>: Glossary. (line 297) * Free Software Foundation (FSF) <2>: Getting. (line 10) * Free Software Foundation (FSF): Manual History. (line 6) -* FreeBSD: Glossary. (line 624) +* FreeBSD: Glossary. (line 616) * FS variable <1>: User-modified. (line 56) * FS variable: Field Separators. (line 15) * FS variable, --field-separator option and: Options. (line 21) @@ -31253,7 +31480,8 @@ Index (line 6) * FS, containing ^: Regexp Field Splitting. (line 59) -* FSF (Free Software Foundation) <1>: Glossary. (line 305) +* FS, in multiline records: Multiple Line. (line 41) +* FSF (Free Software Foundation) <1>: Glossary. (line 297) * FSF (Free Software Foundation) <2>: Getting. (line 10) * FSF (Free Software Foundation): Manual History. (line 6) * fts() extension function: Extension Sample File Functions. @@ -31261,6 +31489,7 @@ Index * FUNCTAB array: Auto-set. (line 128) * function calls: Function Calls. (line 6) * function calls, indirect: Indirect Calls. (line 6) +* function definition example: Function Example. (line 6) * function pointers: Indirect Calls. (line 6) * functions, arrays as parameters to: Pass By Value/Reference. (line 47) @@ -31297,8 +31526,8 @@ Index * functions, undefined: Pass By Value/Reference. (line 71) * functions, user-defined: User-defined. (line 6) -* functions, user-defined, calling: Calling A Function. (line 6) -* functions, user-defined, counts: Profiling. (line 129) +* functions, user-defined, calling: Function Caveats. (line 6) +* functions, user-defined, counts, in a profile: Profiling. (line 137) * functions, user-defined, library of: Library Functions. (line 6) * functions, user-defined, next/nextfile statements and <1>: Nextfile Statement. (line 47) @@ -31306,7 +31535,8 @@ Index (line 45) * G-d: Acknowledgments. (line 78) * Garfinkle, Scott: Contributors. (line 34) -* gawk program, dynamic profiling: Profiling. (line 172) +* gawk program, dynamic profiling: Profiling. (line 179) +* gawk version: Auto-set. (line 213) * gawk, ARGIND variable in: Other Arguments. (line 12) * gawk, awk and <1>: This Manual. (line 14) * gawk, awk and: Preface. (line 23) @@ -31315,7 +31545,7 @@ Index * gawk, built-in variables and: Built-in Variables. (line 14) * gawk, character classes and: Bracket Expressions. (line 90) * gawk, coding style in: Adding Code. (line 38) -* gawk, command-line options: GNU Regexp Operators. +* gawk, command-line options, and regular expressions: GNU Regexp Operators. (line 70) * gawk, comparison operators and: Comparison Operators. (line 50) @@ -31349,7 +31579,7 @@ Index * gawk, hexadecimal numbers and: Nondecimal-numbers. (line 42) * gawk, IGNORECASE variable in <1>: Array Sorting Functions. (line 83) -* gawk, IGNORECASE variable in <2>: String Functions. (line 32) +* gawk, IGNORECASE variable in <2>: String Functions. (line 48) * gawk, IGNORECASE variable in <3>: Array Intro. (line 91) * gawk, IGNORECASE variable in <4>: User-modified. (line 82) * gawk, IGNORECASE variable in: Case-sensitivity. (line 26) @@ -31368,11 +31598,11 @@ Index * gawk, line continuation in: Conditional Exp. (line 34) * gawk, LINT variable in: User-modified. (line 98) * gawk, list of contributors to: Contributors. (line 6) -* gawk, MS-DOS version of: PC Using. (line 11) -* gawk, MS-Windows version of: PC Using. (line 11) +* gawk, MS-DOS version of: PC Using. (line 10) +* gawk, MS-Windows version of: PC Using. (line 10) * gawk, newlines in: Statements/Lines. (line 12) * gawk, octal numbers and: Nondecimal-numbers. (line 42) -* gawk, OS/2 version of: PC Using. (line 11) +* gawk, OS/2 version of: PC Using. (line 10) * gawk, PROCINFO array in <1>: Two-way I/O. (line 116) * gawk, PROCINFO array in <2>: Time Functions. (line 47) * gawk, PROCINFO array in: Auto-set. (line 142) @@ -31384,10 +31614,8 @@ Index (line 6) * gawk, regular expressions, precedence: Regexp Operators. (line 161) * gawk, RT variable in <1>: Auto-set. (line 275) -* gawk, RT variable in <2>: Getline/Variable/File. - (line 10) -* gawk, RT variable in <3>: Multiple Line. (line 129) -* gawk, RT variable in: Records. (line 117) +* gawk, RT variable in <2>: Multiple Line. (line 129) +* gawk, RT variable in: Records. (line 132) * gawk, See Also awk: Preface. (line 36) * gawk, source code, obtaining: Getting. (line 6) * gawk, splitting fields and: Constant Size. (line 88) @@ -31400,11 +31628,13 @@ Index * gawk, VMS version of: VMS Installation. (line 6) * gawk, word-boundary operator: GNU Regexp Operators. (line 63) +* gawkextlib: gawkextlib. (line 6) * gawkextlib project: gawkextlib. (line 6) -* General Public License (GPL): Glossary. (line 314) +* General Public License (GPL): Glossary. (line 306) * General Public License, See GPL: Manual History. (line 11) -* gensub() function (gawk) <1>: String Functions. (line 81) -* gensub() function (gawk): Using Constant Regexps. +* generate time values: Time Functions. (line 25) +* gensub <1>: String Functions. (line 82) +* gensub: Using Constant Regexps. (line 43) * gensub() function (gawk), escape processing: Gory Details. (line 6) * getaddrinfo() function (C library): TCP/IP Networking. (line 38) @@ -31429,6 +31659,8 @@ Index * getline command, FILENAME variable and: Getline Notes. (line 19) * getline command, return values: Getline. (line 19) * getline command, variants: Getline Summary. (line 6) +* getline from a file: Getline/File. (line 6) +* getline into a variable: Getline/Variable. (line 6) * getline statement, BEGINFILE/ENDFILE patterns and: BEGINFILE/ENDFILE. (line 54) * getlocaltime() user-defined function: Getlocaltime Function. @@ -31446,40 +31678,47 @@ Index * gettext() function (C library): Explaining gettext. (line 62) * gettimeofday() extension function: Extension Sample Time. (line 13) -* GMP: Arbitrary Precision Arithmetic. - (line 6) +* git utility <1>: Adding Code. (line 111) +* git utility <2>: Accessing The Source. + (line 10) +* git utility <3>: Other Versions. (line 29) +* git utility: gawkextlib. (line 29) +* git, use of for gawk source code: Derived Files. (line 6) +* GMP: Gawk and MPFR. (line 6) * GNITS mailing list: Acknowledgments. (line 52) * GNU awk, See gawk: Preface. (line 49) * GNU Free Documentation License: GNU Free Documentation License. - (line 6) -* GNU General Public License: Glossary. (line 314) -* GNU Lesser General Public License: Glossary. (line 405) + (line 7) +* GNU General Public License: Glossary. (line 306) +* GNU Lesser General Public License: Glossary. (line 397) * GNU long options <1>: Options. (line 6) * GNU long options: Command Line. (line 13) * GNU long options, printing list of: Options. (line 154) -* GNU Project <1>: Glossary. (line 323) +* GNU Project <1>: Glossary. (line 315) * GNU Project: Manual History. (line 11) -* GNU/Linux <1>: Glossary. (line 624) +* GNU/Linux <1>: Glossary. (line 616) * GNU/Linux <2>: I18N Example. (line 55) * GNU/Linux: Manual History. (line 28) -* GPL (General Public License) <1>: Glossary. (line 314) +* Gordon, Assaf: Contributors. (line 105) +* GPL (General Public License) <1>: Glossary. (line 306) * GPL (General Public License): Manual History. (line 11) * GPL (General Public License), printing: Options. (line 88) * grcat program: Group Functions. (line 16) * Grigera, Juan: Contributors. (line 57) * group database, reading: Group Functions. (line 6) * group file: Group Functions. (line 6) +* group ID of gawk user: Auto-set. (line 186) * groups, information about: Group Functions. (line 6) -* gsub() function <1>: String Functions. (line 134) -* gsub() function: Using Constant Regexps. +* gsub <1>: String Functions. (line 135) +* gsub: Using Constant Regexps. (line 43) -* gsub() function, arguments of: String Functions. (line 459) +* gsub() function, arguments of: String Functions. (line 460) * gsub() function, escape processing: Gory Details. (line 6) * h debugger command (alias for help): Miscellaneous Debugger Commands. (line 66) * Hankerson, Darrel <1>: Contributors. (line 60) * Hankerson, Darrel: Acknowledgments. (line 60) -* Haque, John: Contributors. (line 105) +* Haque, John: Contributors. (line 108) * Hartholz, Elaine: Acknowledgments. (line 38) * Hartholz, Marshall: Acknowledgments. (line 38) * Hasegawa, Isamu: Contributors. (line 94) @@ -31487,9 +31726,10 @@ Index (line 66) * hexadecimal numbers: Nondecimal-numbers. (line 6) * hexadecimal values, enabling interpretation of: Options. (line 207) +* history expansion, in debugger: Readline Support. (line 6) * histsort.awk program: History Sorting. (line 25) * Hughes, Phil: Acknowledgments. (line 43) -* HUP signal: Profiling. (line 204) +* HUP signal, for dynamic profiling: Profiling. (line 211) * hyphen (-), - operator: Precedence. (line 52) * hyphen (-), -- operator <1>: Precedence. (line 46) * hyphen (-), -- operator: Increment Ops. (line 48) @@ -31502,38 +31742,38 @@ Index * id.awk program: Id Program. (line 30) * IEEE-754 format: Floating-point Representation. (line 6) -* if statement <1>: If Statement. (line 6) -* if statement: Regexp Usage. (line 19) +* if statement: If Statement. (line 6) * if statement, actions, changing: Ranges. (line 25) +* if statement, use of regexps in: Regexp Usage. (line 19) * igawk.sh program: Igawk Program. (line 124) +* ignore breakpoint: Breakpoint Control. (line 87) * ignore debugger command: Breakpoint Control. (line 87) -* IGNORECASE variable <1>: Array Sorting Functions. - (line 83) -* IGNORECASE variable <2>: String Functions. (line 32) -* IGNORECASE variable <3>: Array Intro. (line 91) -* IGNORECASE variable <4>: User-modified. (line 82) -* IGNORECASE variable: Case-sensitivity. (line 26) -* IGNORECASE variable, array sorting and: Array Sorting Functions. +* IGNORECASE variable: User-modified. (line 82) +* IGNORECASE variable, and array indices: Array Intro. (line 91) +* IGNORECASE variable, and array sorting functions: Array Sorting Functions. (line 83) -* IGNORECASE variable, array subscripts and: Array Intro. (line 91) * IGNORECASE variable, in example programs: Library Functions. (line 53) +* IGNORECASE variable, with ~ and !~ operators: Case-sensitivity. + (line 26) * Illumos: Other Versions. (line 104) * Illumos, POSIX-compliant awk: Other Versions. (line 104) * implementation issues, gawk: Notes. (line 6) * implementation issues, gawk, debugging: Compatibility Mode. (line 6) * implementation issues, gawk, limits <1>: Redirection. (line 135) * implementation issues, gawk, limits: Getline Notes. (line 14) -* in operator <1>: Id Program. (line 93) -* in operator <2>: Scanning an Array. (line 17) -* in operator <3>: Reference to Elements. - (line 37) -* in operator <4>: For Statement. (line 75) -* in operator <5>: Precedence. (line 83) +* in operator <1>: For Statement. (line 75) +* in operator <2>: Precedence. (line 83) * in operator: Comparison Operators. (line 11) +* in operator, index existence in multidimensional arrays: Multidimensional. + (line 43) +* in operator, order of array access: Scanning an Array. (line 48) +* in operator, testing if array element exists: Reference to Elements. + (line 37) +* in operator, use in loops: Scanning an Array. (line 17) * increment operators: Increment Ops. (line 6) -* index() function: String Functions. (line 150) +* index: String Functions. (line 151) * indexing arrays: Array Intro. (line 49) * indirect function calls: Indirect Calls. (line 6) * infinite precision: Arbitrary Precision Arithmetic. @@ -31551,6 +31791,7 @@ Index * input files, running awk without: Read Terminal. (line 6) * input files, variable assignments and: Other Arguments. (line 19) * input pipeline: Getline/Pipe. (line 9) +* input record, length of: String Functions. (line 171) * input redirection: Getline/File. (line 6) * input, data, nondecimal: Nondecimal Data. (line 6) * input, explicit: Getline. (line 6) @@ -31559,17 +31800,21 @@ Index * input, splitting into records: Records. (line 6) * input, standard <1>: Special FD. (line 6) * input, standard: Read Terminal. (line 6) +* input/output functions: I/O Functions. (line 6) * input/output, binary: User-modified. (line 10) * input/output, from BEGIN and END: I/O And BEGIN/END. (line 6) * input/output, two-way: Two-way I/O. (line 44) * insomnia, cure for: Alarm Program. (line 6) * installation, VMS: VMS Installation. (line 6) * installing gawk: Installation. (line 6) -* INT signal (MS-Windows): Profiling. (line 207) -* int() function: Numeric Functions. (line 23) -* integer, arbitrary precision: Arbitrary Precision Integers. - (line 6) +* instruction tracing, in debugger: Debugger Info. (line 89) +* int: Numeric Functions. (line 23) +* INT signal (MS-Windows): Profiling. (line 214) +* integer array indices: Numeric Array Subscripts. + (line 31) * integers: General Arithmetic. (line 6) +* integers, arbitrary precision: Arbitrary Precision Integers. + (line 6) * integers, unsigned: General Arithmetic. (line 15) * interacting with other programs: I/O Functions. (line 72) * internationalization <1>: I18N and L10N. (line 6) @@ -31588,19 +31833,20 @@ Index * internationalization, localization, portability and: I18N Portability. (line 6) * internationalizing a program: Explaining gettext. (line 6) -* interpreted programs <1>: Glossary. (line 365) +* interpreted programs <1>: Glossary. (line 357) * interpreted programs: Basic High Level. (line 15) -* interval expressions: Regexp Operators. (line 116) +* interval expressions, regexp operator: Regexp Operators. (line 116) * inventory-shipped file: Sample Data Files. (line 32) -* isarray() function (gawk): Type Functions. (line 11) -* ISO: Glossary. (line 376) -* ISO 8859-1: Glossary. (line 141) -* ISO Latin-1: Glossary. (line 141) +* invoke shell command: I/O Functions. (line 72) +* isarray: Type Functions. (line 11) +* ISO: Glossary. (line 368) +* ISO 8859-1: Glossary. (line 133) +* ISO Latin-1: Glossary. (line 133) * Jacobs, Andrew: Passwd Functions. (line 90) * Jaegermann, Michal <1>: Contributors. (line 45) * Jaegermann, Michal: Acknowledgments. (line 60) * Java implementation of awk: Other Versions. (line 112) -* Java programming language: Glossary. (line 388) +* Java programming language: Glossary. (line 380) * jawk: Other Versions. (line 112) * Jedi knights: Undocumented. (line 6) * join() user-defined function: Join Function. (line 18) @@ -31608,15 +31854,18 @@ Index * Kahrs, Ju"rgen: Acknowledgments. (line 60) * Kasal, Stepan: Acknowledgments. (line 60) * Kenobi, Obi-Wan: Undocumented. (line 6) -* Kernighan, Brian <1>: Basic Data Typing. (line 55) -* Kernighan, Brian <2>: Other Versions. (line 13) -* Kernighan, Brian <3>: Contributors. (line 11) -* Kernighan, Brian <4>: BTL. (line 6) -* Kernighan, Brian <5>: Concatenation. (line 6) -* Kernighan, Brian <6>: Acknowledgments. (line 72) -* Kernighan, Brian <7>: Conventions. (line 34) +* Kernighan, Brian <1>: Glossary. (line 143) +* Kernighan, Brian <2>: Basic Data Typing. (line 55) +* Kernighan, Brian <3>: Other Versions. (line 13) +* Kernighan, Brian <4>: Contributors. (line 11) +* Kernighan, Brian <5>: BTL. (line 6) +* Kernighan, Brian <6>: Library Functions. (line 12) +* Kernighan, Brian <7>: Concatenation. (line 6) +* Kernighan, Brian <8>: Getline/Pipe. (line 6) +* Kernighan, Brian <9>: Acknowledgments. (line 72) +* Kernighan, Brian <10>: Conventions. (line 34) * Kernighan, Brian: History. (line 17) -* kill command, dynamic profiling: Profiling. (line 181) +* kill command, dynamic profiling: Profiling. (line 188) * Knights, jedi: Undocumented. (line 6) * Knuth, Donald: Arbitrary Precision Arithmetic. (line 6) @@ -31643,11 +31892,14 @@ Index * left angle bracket (<), <= operator <1>: Precedence. (line 65) * left angle bracket (<), <= operator: Comparison Operators. (line 11) +* left shift: Bitwise Functions. (line 46) * left shift, bitwise: Bitwise Functions. (line 32) * leftmost longest match: Multiple Line. (line 26) -* length() function: String Functions. (line 163) -* Lesser General Public License (LGPL): Glossary. (line 405) -* LGPL (Lesser General Public License): Glossary. (line 405) +* length: String Functions. (line 164) +* length of input record: String Functions. (line 171) +* length of string: String Functions. (line 164) +* Lesser General Public License (LGPL): Glossary. (line 397) +* LGPL (Lesser General Public License): Glossary. (line 397) * libmawk: Other Versions. (line 120) * libraries of awk functions: Library Functions. (line 6) * libraries of awk functions, assertions: Assert Function. (line 6) @@ -31692,50 +31944,65 @@ Index * lint checking, undefined functions: Pass By Value/Reference. (line 88) * LINT variable: User-modified. (line 98) -* Linux <1>: Glossary. (line 624) +* Linux <1>: Glossary. (line 616) * Linux <2>: I18N Example. (line 55) * Linux: Manual History. (line 28) +* list all global variables, in debugger: Debugger Info. (line 48) * list debugger command: Miscellaneous Debugger Commands. (line 72) +* list function definitions, in debugger: Debugger Info. (line 30) * loading, library: Options. (line 173) -* local variables: Variable Scope. (line 6) +* local variables, in a function: Variable Scope. (line 6) * locale categories: Explaining gettext. (line 80) * locale decimal point character: Options. (line 263) * locale, definition of: Locales. (line 6) * localization: I18N and L10N. (line 6) * localization, See internationalization, localization: I18N and L10N. (line 6) +* log: Numeric Functions. (line 30) * log files, timestamps in: Time Functions. (line 6) -* log() function: Numeric Functions. (line 30) +* logarithm: Numeric Functions. (line 30) * logical false/true: Truth Values. (line 6) * logical operators, See Boolean expressions: Boolean Ops. (line 6) * login information: Passwd Functions. (line 16) * long options: Command Line. (line 13) * loops: While Statement. (line 6) +* loops, break statement and: Break Statement. (line 6) * loops, continue statements and: For Statement. (line 64) -* loops, count for header: Profiling. (line 123) +* loops, count for header, in a profile: Profiling. (line 131) +* loops, do-while: Do Statement. (line 6) * loops, exiting: Break Statement. (line 6) +* loops, for, array scanning: Scanning an Array. (line 6) +* loops, for, iterative: For Statement. (line 6) * loops, See Also while statement: While Statement. (line 6) +* loops, while: While Statement. (line 6) * ls utility: More Complex. (line 15) -* lshift() function (gawk): Bitwise Functions. (line 46) +* lshift: Bitwise Functions. (line 46) * lvalues/rvalues: Assignment Ops. (line 32) +* mail-list file: Sample Data Files. (line 6) * mailing labels, printing: Labels Program. (line 6) * mailing list, GNITS: Acknowledgments. (line 52) -* Malmberg, John <1>: Bugs. (line 72) +* Malmberg, John <1>: Bugs. (line 70) * Malmberg, John: Acknowledgments. (line 60) * mark parity: Ordinal Functions. (line 45) * marked string extraction (internationalization): String Extraction. (line 6) * marked strings, extracting: String Extraction. (line 6) * Marx, Groucho: Increment Ops. (line 60) -* match() function: String Functions. (line 203) +* match: String Functions. (line 204) +* match regexp in string: String Functions. (line 204) * match() function, RSTART/RLENGTH variables: String Functions. - (line 220) + (line 221) * matching, expressions, See comparison expressions: Typing and Comparison. (line 9) * matching, leftmost longest: Multiple Line. (line 26) * matching, null strings: Gory Details. (line 164) -* mawk program: Other Versions. (line 44) +* mawk utility <1>: Other Versions. (line 44) +* mawk utility <2>: Nextfile Statement. (line 47) +* mawk utility <3>: Concatenation. (line 36) +* mawk utility <4>: Getline/Pipe. (line 62) +* mawk utility: Escape Sequences. (line 124) +* maximum precision supported by MPFR library: Auto-set. (line 227) * McPhee, Patrick: Contributors. (line 100) * message object files: Explaining gettext. (line 41) * message object files, converting from portable object files: I18N Example. @@ -31744,15 +32011,18 @@ Index (line 47) * message object files, specifying directory of: Explaining gettext. (line 53) +* messages from extensions: Printing Messages. (line 6) +* metacharacters in regular expressions: Regexp Operators. (line 6) * metacharacters, escape sequences for: Escape Sequences. (line 130) -* mktime() function (gawk): Time Functions. (line 25) +* minimum precision supported by MPFR library: Auto-set. (line 230) +* mktime: Time Functions. (line 25) * modifiers, in format specifiers: Format Modifiers. (line 6) * monetary information, localization: Explaining gettext. (line 103) -* MPFR: Arbitrary Precision Arithmetic. - (line 6) +* MPFR: Gawk and MPFR. (line 6) * msgfmt utility: I18N Example. (line 62) * multiple precision: Arbitrary Precision Arithmetic. (line 6) +* multiple-line records: Multiple Line. (line 6) * n debugger command (alias for next): Debugger Execution Control. (line 43) * names, arrays/variables <1>: Library Names. (line 6) @@ -31764,7 +32034,7 @@ Index * namespace issues, functions: Definition Syntax. (line 20) * nawk utility: Names. (line 17) * negative zero: Unexpected Results. (line 34) -* NetBSD: Glossary. (line 624) +* NetBSD: Glossary. (line 616) * networks, programming: TCP/IP Networking. (line 6) * networks, support for: Special Network. (line 6) * newlines <1>: Boolean Ops. (line 67) @@ -31803,6 +32073,8 @@ Index * ni debugger command (alias for nexti): Debugger Execution Control. (line 49) * noassign.awk program: Ignoring Assigns. (line 15) +* non-existent array elements: Reference to Elements. + (line 23) * not Boolean-logic operator: Boolean Ops. (line 6) * NR variable <1>: Auto-set. (line 137) * NR variable: Records. (line 6) @@ -31811,13 +32083,15 @@ Index * null strings <2>: Truth Values. (line 6) * null strings <3>: Regexp Field Splitting. (line 43) -* null strings: Records. (line 107) -* null strings, array elements and: Delete. (line 27) +* null strings: Records. (line 122) +* null strings in gawk arguments, quoting and: Quoting. (line 62) +* null strings, and deleting array elements: Delete. (line 27) * null strings, as array subscripts: Uninitialized Subscripts. (line 43) * null strings, converting numbers to strings: Conversion. (line 21) * null strings, matching: Gory Details. (line 164) -* null strings, quoting and: Quoting. (line 62) +* number as string of bits: Bitwise Functions. (line 109) +* number of array elements: String Functions. (line 194) * number sign (#), #! (executable scripts): Executable Scripts. (line 6) * number sign (#), commenting: Comments. (line 6) @@ -31832,9 +32106,9 @@ Index * numbers, floating-point: General Arithmetic. (line 6) * numbers, hexadecimal: Nondecimal-numbers. (line 6) * numbers, octal: Nondecimal-numbers. (line 6) -* numbers, random: Numeric Functions. (line 64) * numbers, rounding: Round Function. (line 6) -* numeric, constants: Scalar Constants. (line 6) +* numeric constants: Scalar Constants. (line 6) +* numeric functions: Numeric Functions. (line 6) * numeric, output format: OFMT. (line 6) * numeric, strings: Variable Typing. (line 6) * o debugger command (alias for option): Debugger Info. (line 57) @@ -31849,7 +32123,7 @@ Index * OFS variable <1>: User-modified. (line 124) * OFS variable <2>: Output Separators. (line 6) * OFS variable: Changing Fields. (line 64) -* OpenBSD: Glossary. (line 624) +* OpenBSD: Glossary. (line 616) * OpenSolaris: Other Versions. (line 96) * operating systems, BSD-based: Manual History. (line 28) * operating systems, PC, gawk on: PC Using. (line 6) @@ -31884,10 +32158,7 @@ Index * operators, word-boundary (gawk): GNU Regexp Operators. (line 63) * option debugger command: Debugger Info. (line 57) -* options, command-line <1>: Command Line Field Separator. - (line 6) -* options, command-line <2>: Options. (line 6) -* options, command-line: Long. (line 12) +* options, command-line: Options. (line 6) * options, command-line, end of: Options. (line 54) * options, command-line, invoking awk: Command Line. (line 6) * options, command-line, processing: Getopt Function. (line 6) @@ -31895,9 +32166,9 @@ Index * options, long <1>: Options. (line 6) * options, long: Command Line. (line 13) * options, printing list of: Options. (line 154) +* or: Bitwise Functions. (line 49) * OR bitwise operation: Bitwise Functions. (line 6) * or Boolean-logic operator: Boolean Ops. (line 6) -* or() function (gawk): Bitwise Functions. (line 49) * ord() extension function: Extension Sample Ord. (line 12) * ord() user-defined function: Ordinal Functions. (line 16) @@ -31908,6 +32179,7 @@ Index * output record separator, See ORS variable: Output Separators. (line 20) * output redirection: Redirection. (line 6) +* output wrapper: Output Wrappers. (line 6) * output, buffering: I/O Functions. (line 29) * output, duplicating into files: Tee Program. (line 6) * output, files, closing: Close Files And Pipes. @@ -31920,20 +32192,21 @@ Index * output, standard: Special FD. (line 6) * p debugger command (alias for print): Viewing And Changing Data. (line 36) -* P1003.1 POSIX standard: Glossary. (line 462) -* parentheses () <1>: Profiling. (line 138) -* parentheses (): Regexp Operators. (line 79) +* P1003.1 POSIX standard: Glossary. (line 454) +* parent process ID of gawk process: Auto-set. (line 195) +* parentheses (), in a profile: Profiling. (line 146) +* parentheses (), regexp operator: Regexp Operators. (line 79) * password file: Passwd Functions. (line 16) -* patsplit() function (gawk): String Functions. (line 290) +* patsplit: String Functions. (line 291) * patterns: Patterns and Actions. (line 6) * patterns, comparison expressions as: Expression Patterns. (line 14) -* patterns, counts: Profiling. (line 110) +* patterns, counts, in a profile: Profiling. (line 118) * patterns, default: Very Simple. (line 34) * patterns, empty: Empty. (line 6) * patterns, expressions as: Regexp Patterns. (line 6) * patterns, ranges in: Ranges. (line 6) -* patterns, regexp constants as: Expression Patterns. (line 36) +* patterns, regexp constants as: Expression Patterns. (line 34) * patterns, types of: Pattern Overview. (line 15) * pawk (profiling version of Brian Kernighan's awk): Other Versions. (line 78) @@ -31943,22 +32216,24 @@ Index * percent sign (%), % operator: Precedence. (line 55) * percent sign (%), %= operator <1>: Precedence. (line 95) * percent sign (%), %= operator: Assignment Ops. (line 129) -* period (.): Regexp Operators. (line 43) +* period (.), regexp operator: Regexp Operators. (line 43) * Perl: Future Extensions. (line 6) * Peters, Arno: Contributors. (line 85) * Peterson, Hal: Contributors. (line 39) -* pipes, closing: Close Files And Pipes. +* pipe, closing: Close Files And Pipes. (line 6) -* pipes, input: Getline/Pipe. (line 9) -* pipes, output: Redirection. (line 57) -* Pitts, Dave <1>: Bugs. (line 73) +* pipe, input: Getline/Pipe. (line 9) +* pipe, output: Redirection. (line 57) +* Pitts, Dave <1>: Bugs. (line 70) * Pitts, Dave: Acknowledgments. (line 60) -* plus sign (+): Regexp Operators. (line 102) +* Plauger, P.J.: Library Functions. (line 12) +* plug-in: Extension Intro. (line 6) * plus sign (+), + operator: Precedence. (line 52) * plus sign (+), ++ operator <1>: Precedence. (line 46) * plus sign (+), ++ operator: Increment Ops. (line 11) * plus sign (+), += operator <1>: Precedence. (line 95) * plus sign (+), += operator: Assignment Ops. (line 82) +* plus sign (+), regexp operator: Regexp Operators. (line 102) * pointers to functions: Indirect Calls. (line 6) * portability: Escape Sequences. (line 94) * portability, #! (executable scripts): Executable Scripts. (line 33) @@ -31970,14 +32245,14 @@ Index (line 112) * portability, close() function and: Close Files And Pipes. (line 81) -* portability, data files as single record: Records. (line 179) +* portability, data files as single record: Records. (line 194) * portability, deleting array elements: Delete. (line 56) * portability, example programs: Library Functions. (line 42) * portability, functions, defining: Definition Syntax. (line 99) * portability, gawk: New Ports. (line 6) * portability, gettext library and: Explaining gettext. (line 10) * portability, internationalization and: I18N Portability. (line 6) -* portability, length() function: String Functions. (line 172) +* portability, length() function: String Functions. (line 173) * portability, new awk vs. old awk: Conversion. (line 55) * portability, next statement in user-defined functions: Pass By Value/Reference. (line 91) @@ -31985,7 +32260,7 @@ Index * portability, operators: Increment Ops. (line 60) * portability, operators, not in POSIX awk: Precedence. (line 98) * portability, POSIXLY_CORRECT environment variable: Options. (line 353) -* portability, substr() function: String Functions. (line 509) +* portability, substr() function: String Functions. (line 510) * portable object files <1>: Translator i18n. (line 6) * portable object files: Explaining gettext. (line 36) * portable object files, converting to message object files: I18N Example. @@ -32015,14 +32290,14 @@ Index * POSIX awk, changes in awk versions: POSIX. (line 6) * POSIX awk, continue statement and: Continue Statement. (line 43) * POSIX awk, CONVFMT variable and: User-modified. (line 28) -* POSIX awk, date utility and: Time Functions. (line 262) +* POSIX awk, date utility and: Time Functions. (line 263) * POSIX awk, field separators and <1>: Field Splitting Summary. (line 40) * POSIX awk, field separators and: Fields. (line 6) * POSIX awk, FS variable and: User-modified. (line 66) * POSIX awk, function keyword in: Definition Syntax. (line 83) * POSIX awk, functions and, gsub()/sub(): Gory Details. (line 54) -* POSIX awk, functions and, length(): String Functions. (line 172) +* POSIX awk, functions and, length(): String Functions. (line 173) * POSIX awk, GNU long options and: Options. (line 15) * POSIX awk, interval expressions in: Regexp Operators. (line 135) * POSIX awk, next/nextfile statements and: Next Statement. (line 45) @@ -32055,6 +32330,8 @@ Index * print statement, See Also redirection, of output: Redirection. (line 17) * print statement, sprintf() function and: Round Function. (line 6) +* print variables, in debugger: Viewing And Changing Data. + (line 36) * printf debugger command: Viewing And Changing Data. (line 54) * printf statement <1>: Printf. (line 6) @@ -32074,22 +32351,30 @@ Index * printf statement, sprintf() function and: Round Function. (line 6) * printf statement, syntax of: Basic Printf. (line 6) * printing: Printing. (line 6) +* printing messages from extensions: Printing Messages. (line 6) * printing, list of options: Options. (line 154) * printing, mailing labels: Labels Program. (line 6) * printing, unduplicated lines of text: Uniq Program. (line 6) * printing, user information: Id Program. (line 6) * private variables: Library Names. (line 11) +* process group idIDof gawk process: Auto-set. (line 189) +* process ID of gawk process: Auto-set. (line 192) * processes, two-way communications with: Two-way I/O. (line 23) * processing data: Basic High Level. (line 6) -* PROCINFO array <1>: Two-way I/O. (line 116) -* PROCINFO array <2>: Id Program. (line 15) -* PROCINFO array <3>: Group Functions. (line 6) -* PROCINFO array <4>: Passwd Functions. (line 6) -* PROCINFO array <5>: Time Functions. (line 47) -* PROCINFO array <6>: Auto-set. (line 142) -* PROCINFO array: Obsolete. (line 11) +* PROCINFO array <1>: Passwd Functions. (line 6) +* PROCINFO array <2>: Time Functions. (line 47) +* PROCINFO array: Auto-set. (line 142) +* PROCINFO array, and communications via ptys: Two-way I/O. (line 116) +* PROCINFO array, and group membership: Group Functions. (line 6) +* PROCINFO array, and user and group ID numbers: Id Program. (line 15) +* PROCINFO array, testing the field splitting: Passwd Functions. + (line 161) +* PROCINFO array, uses: Auto-set. (line 248) +* PROCINFO, values of sorted_in: Controlling Scanning. + (line 24) * profiling awk programs: Profiling. (line 6) -* profiling awk programs, dynamically: Profiling. (line 172) +* profiling awk programs, dynamically: Profiling. (line 179) +* program identifiers: Auto-set. (line 160) * program, definition of: Getting Started. (line 21) * programmers, attractiveness of: Two-way I/O. (line 6) * programming conventions, --non-decimal-data option: Nondecimal Data. @@ -32107,10 +32392,10 @@ Index * programming conventions, private variable names: Library Names. (line 23) * programming language, recipe for: History. (line 6) -* Programming languages, Ada: Glossary. (line 20) +* programming languages, Ada: Glossary. (line 20) * programming languages, data-driven vs. procedural: Getting Started. (line 12) -* Programming languages, Java: Glossary. (line 388) +* programming languages, Java: Glossary. (line 380) * programming, basic steps: Basic High Level. (line 20) * programming, concepts: Basic Concepts. (line 6) * pwcat program: Passwd Functions. (line 23) @@ -32118,24 +32403,23 @@ Index (line 99) * QSE Awk: Other Versions. (line 130) * Quanstrom, Erik: Alarm Program. (line 8) -* question mark (?) regexp operator <1>: GNU Regexp Operators. - (line 59) -* question mark (?) regexp operator: Regexp Operators. (line 111) * question mark (?), ?: operator: Precedence. (line 92) +* question mark (?), regexp operator <1>: GNU Regexp Operators. + (line 59) +* question mark (?), regexp operator: Regexp Operators. (line 111) * QuikTrim Awk: Other Versions. (line 134) * quit debugger command: Miscellaneous Debugger Commands. (line 99) -* QUIT signal (MS-Windows): Profiling. (line 207) -* quoting <1>: Comments. (line 27) -* quoting <2>: Long. (line 26) -* quoting: Read Terminal. (line 25) -* quoting, rules for: Quoting. (line 6) -* quoting, tricks for: Quoting. (line 71) +* QUIT signal (MS-Windows): Profiling. (line 214) +* quoting in gawk command lines: Long. (line 26) +* quoting in gawk command lines, tricks for: Quoting. (line 71) +* quoting, for small awk programs: Comments. (line 27) * r debugger command (alias for run): Debugger Execution Control. (line 62) * Rakitzis, Byron: History Sorting. (line 25) +* Ramey, Chet <1>: General Data Types. (line 6) * Ramey, Chet: Acknowledgments. (line 60) -* rand() function: Numeric Functions. (line 34) +* rand: Numeric Functions. (line 34) * random numbers, Cliff: Cliff Random Function. (line 6) * random numbers, rand()/srand() functions: Numeric Functions. @@ -32143,7 +32427,8 @@ Index * random numbers, seed of: Numeric Functions. (line 64) * range expressions (regexps): Bracket Expressions. (line 6) * range patterns: Ranges. (line 6) -* Rankin, Pat <1>: Bugs. (line 72) +* range patterns, line continuation and: Ranges. (line 65) +* Rankin, Pat <1>: Bugs. (line 70) * Rankin, Pat <2>: Contributors. (line 37) * Rankin, Pat <3>: Assignment Ops. (line 100) * Rankin, Pat: Acknowledgments. (line 60) @@ -32154,37 +32439,41 @@ Index * readdir extension: Extension Sample Readdir. (line 9) * readfile() extension function: Extension Sample Readfile. - (line 11) + (line 12) * readfile() user-defined function: Readfile Function. (line 30) +* reading input files: Reading Files. (line 6) * recipe for a programming language: History. (line 6) * record separators <1>: User-modified. (line 143) * record separators: Records. (line 14) -* record separators, changing: Records. (line 81) -* record separators, regular expressions as: Records. (line 117) +* record separators, changing: Records. (line 93) +* record separators, regular expressions as: Records. (line 132) * record separators, with multiline records: Multiple Line. (line 10) * records <1>: Basic High Level. (line 73) * records: Reading Files. (line 14) * records, multiline: Multiple Line. (line 6) * records, printing: Print. (line 22) * records, splitting input into: Records. (line 6) -* records, terminating: Records. (line 117) -* records, treating files as: Records. (line 204) +* records, terminating: Records. (line 132) +* records, treating files as: Records. (line 219) * recursive functions: Definition Syntax. (line 73) +* redirect gawk output, in debugger: Debugger Info. (line 72) * redirection of input: Getline/File. (line 6) * redirection of output: Redirection. (line 6) * reference counting, sorting arrays: Array Sorting Functions. (line 77) +* regexp: Regexp. (line 6) * regexp constants <1>: Comparison Operators. (line 102) * regexp constants <2>: Regexp Constants. (line 6) * regexp constants: Regexp Usage. (line 57) * regexp constants, /=.../, /= operator and: Assignment Ops. (line 147) -* regexp constants, as patterns: Expression Patterns. (line 36) +* regexp constants, as patterns: Expression Patterns. (line 34) * regexp constants, in gawk: Using Constant Regexps. (line 28) * regexp constants, slashes vs. quotes: Computed Regexps. (line 28) * regexp constants, vs. string constants: Computed Regexps. (line 38) -* regexp, See regular expressions: Regexp. (line 6) +* register extension: Registration Functions. + (line 6) * regular expressions: Regexp. (line 6) * regular expressions as field separators: Field Separators. (line 51) * regular expressions, anchors in: Regexp Operators. (line 22) @@ -32192,7 +32481,7 @@ Index (line 6) * regular expressions, as patterns <1>: Regexp Patterns. (line 6) * regular expressions, as patterns: Regexp Usage. (line 6) -* regular expressions, as record separators: Records. (line 117) +* regular expressions, as record separators: Records. (line 132) * regular expressions, case sensitivity <1>: User-modified. (line 82) * regular expressions, case sensitivity: Case-sensitivity. (line 6) * regular expressions, computed: Computed Regexps. (line 6) @@ -32219,12 +32508,13 @@ Index * regular expressions, searching for: Egrep Program. (line 6) * relational operators, See comparison operators: Typing and Comparison. (line 9) +* replace in string: String Functions. (line 406) * return debugger command: Debugger Execution Control. (line 54) * return statement, user-defined functions: Return Statement. (line 6) * return value, close() function: Close Files And Pipes. (line 130) -* rev() user-defined function: Function Example. (line 52) +* rev() user-defined function: Function Example. (line 53) * revoutput extension: Extension Sample Revout. (line 11) * revtwoway extension: Extension Sample Rev2way. @@ -32239,18 +32529,20 @@ Index (line 11) * right angle bracket (>), >> operator (I/O) <1>: Precedence. (line 65) * right angle bracket (>), >> operator (I/O): Redirection. (line 50) +* right shift: Bitwise Functions. (line 52) * right shift, bitwise: Bitwise Functions. (line 32) * Ritchie, Dennis: Basic Data Typing. (line 55) * RLENGTH variable: Auto-set. (line 262) -* RLENGTH variable, match() function and: String Functions. (line 220) +* RLENGTH variable, match() function and: String Functions. (line 221) * Robbins, Arnold <1>: Future Extensions. (line 6) * Robbins, Arnold <2>: Bugs. (line 32) -* Robbins, Arnold <3>: Contributors. (line 132) -* Robbins, Arnold <4>: Alarm Program. (line 6) -* Robbins, Arnold <5>: Passwd Functions. (line 90) -* Robbins, Arnold <6>: Getline/Pipe. (line 39) +* Robbins, Arnold <3>: Contributors. (line 139) +* Robbins, Arnold <4>: General Data Types. (line 6) +* Robbins, Arnold <5>: Alarm Program. (line 6) +* Robbins, Arnold <6>: Passwd Functions. (line 90) +* Robbins, Arnold <7>: Getline/Pipe. (line 39) * Robbins, Arnold: Command Line Field Separator. - (line 80) + (line 73) * Robbins, Bill: Getline/Pipe. (line 39) * Robbins, Harry: Acknowledgments. (line 78) * Robbins, Jean: Acknowledgments. (line 78) @@ -32258,6 +32550,7 @@ Index * Robbins, Miriam <2>: Getline/Pipe. (line 39) * Robbins, Miriam: Acknowledgments. (line 78) * Rommel, Kai Uwe: Contributors. (line 42) +* round to nearest integer: Numeric Functions. (line 23) * round() user-defined function: Round Function. (line 16) * rounding mode, floating-point: Rounding Mode. (line 6) * rounding numbers: Round Function. (line 6) @@ -32267,14 +32560,12 @@ Index * RS variable <1>: User-modified. (line 143) * RS variable: Records. (line 20) * RS variable, multiline records and: Multiple Line. (line 17) -* rshift() function (gawk): Bitwise Functions. (line 52) +* rshift: Bitwise Functions. (line 52) * RSTART variable: Auto-set. (line 268) -* RSTART variable, match() function and: String Functions. (line 220) +* RSTART variable, match() function and: String Functions. (line 221) * RT variable <1>: Auto-set. (line 275) -* RT variable <2>: Getline/Variable/File. - (line 10) -* RT variable <3>: Multiple Line. (line 129) -* RT variable: Records. (line 117) +* RT variable <2>: Multiple Line. (line 129) +* RT variable: Records. (line 132) * Rubin, Paul <1>: Contributors. (line 15) * Rubin, Paul: History. (line 30) * rule, definition of: Getting Started. (line 21) @@ -32283,55 +32574,80 @@ Index * rvalues/lvalues: Assignment Ops. (line 32) * s debugger command (alias for step): Debugger Execution Control. (line 68) +* sample debugging session: Sample Debugging Session. + (line 6) * sandbox mode: Options. (line 279) +* save debugger options: Debugger Info. (line 84) +* scalar or array: Type Functions. (line 11) * scalar values: Basic Data Typing. (line 13) -* Schorr, Andrew <1>: Contributors. (line 128) +* scanning arrays: Scanning an Array. (line 6) +* scanning multidimensional arrays: Multiscanning. (line 11) +* Schorr, Andrew <1>: Contributors. (line 131) * Schorr, Andrew: Acknowledgments. (line 60) * Schreiber, Bert: Acknowledgments. (line 38) * Schreiber, Rita: Acknowledgments. (line 38) +* search and replace in strings: String Functions. (line 82) +* search in string: String Functions. (line 151) * search paths <1>: VMS Running. (line 58) -* search paths <2>: PC Using. (line 11) -* search paths <3>: Igawk Program. (line 368) -* search paths <4>: AWKLIBPATH Variable. (line 6) -* search paths: AWKPATH Variable. (line 6) +* search paths <2>: PC Using. (line 10) +* search paths: Igawk Program. (line 368) * search paths, for shared libraries: AWKLIBPATH Variable. (line 6) * search paths, for source files <1>: VMS Running. (line 58) -* search paths, for source files <2>: PC Using. (line 11) +* search paths, for source files <2>: PC Using. (line 10) * search paths, for source files <3>: Igawk Program. (line 368) * search paths, for source files: AWKPATH Variable. (line 6) -* searching: String Functions. (line 150) * searching, files for regular expressions: Egrep Program. (line 6) * searching, for words: Dupword Program. (line 6) * sed utility <1>: Glossary. (line 12) * sed utility <2>: Simple Sed. (line 6) * sed utility: Field Splitting Summary. (line 46) -* semicolon (;): Statements/Lines. (line 91) -* semicolon (;), AWKPATH variable and: PC Using. (line 11) +* seeding random number generator: Numeric Functions. (line 64) +* semicolon (;), AWKPATH variable and: PC Using. (line 10) * semicolon (;), separating statements in actions <1>: Statements. (line 10) -* semicolon (;), separating statements in actions: Action Overview. +* semicolon (;), separating statements in actions <2>: Action Overview. (line 19) +* semicolon (;), separating statements in actions: Statements/Lines. + (line 91) * separators, field: User-modified. (line 56) * separators, field, FIELDWIDTHS variable and: User-modified. (line 35) * separators, field, FPAT variable and: User-modified. (line 45) * separators, field, POSIX and: Fields. (line 6) * separators, for records <1>: User-modified. (line 143) * separators, for records: Records. (line 14) -* separators, for records, regular expressions as: Records. (line 117) +* separators, for records, regular expressions as: Records. (line 132) * separators, for statements in actions: Action Overview. (line 19) * separators, subscript: User-modified. (line 156) +* set breakpoint: Breakpoint Control. (line 11) * set debugger command: Viewing And Changing Data. (line 59) +* set directory of message catalogs: I18N Functions. (line 12) +* set watchpoint: Viewing And Changing Data. + (line 67) +* setting rounding mode: Setting Rounding Mode. + (line 6) +* setting working precision: Setting Precision. (line 6) +* shadowing of variable values: Definition Syntax. (line 61) +* shell quoting, double quote: Read Terminal. (line 25) +* shell quoting, rules for: Quoting. (line 6) * shells, piping commands into: Redirection. (line 142) * shells, quoting: Using Shell Variables. (line 12) * shells, quoting, rules for: Quoting. (line 18) * shells, scripts: One-shot. (line 22) +* shells, sea: Undocumented. (line 8) * shells, variables: Using Shell Variables. (line 6) * shift, bitwise: Bitwise Functions. (line 32) * short-circuit operators: Boolean Ops. (line 57) +* show all source files, in debugger: Debugger Info. (line 45) +* show breakpoints: Debugger Info. (line 21) +* show function arguments, in debugger: Debugger Info. (line 18) +* show local variables, in debugger: Debugger Info. (line 34) +* show name of current source file, in debugger: Debugger Info. + (line 37) +* show watchpoints: Debugger Info. (line 51) * si debugger command (alias for stepi): Debugger Execution Control. (line 76) * side effects <1>: Increment Ops. (line 11) @@ -32367,7 +32683,7 @@ Index * sidebar, Piping into sh: Redirection. (line 140) * sidebar, Portability Issues with #!: Executable Scripts. (line 31) * sidebar, Recipe For A Programming Language: History. (line 6) -* sidebar, RS = "\0" Is Not Portable: Records. (line 177) +* sidebar, RS = "\0" Is Not Portable: Records. (line 192) * sidebar, So Why Does gawk have BEGINFILE and ENDFILE?: Filetrans Function. (line 83) * sidebar, Syntactic Ambiguities Between /= and Regular Expressions: Assignment Ops. @@ -32377,30 +32693,36 @@ Index (line 56) * sidebar, Using close()'s Return Value: Close Files And Pipes. (line 128) -* SIGHUP signal: Profiling. (line 204) -* SIGINT signal (MS-Windows): Profiling. (line 207) -* signals, HUP/SIGHUP: Profiling. (line 204) -* signals, INT/SIGINT (MS-Windows): Profiling. (line 207) -* signals, QUIT/SIGQUIT (MS-Windows): Profiling. (line 207) -* signals, USR1/SIGUSR1: Profiling. (line 181) -* SIGQUIT signal (MS-Windows): Profiling. (line 207) -* SIGUSR1 signal: Profiling. (line 181) +* SIGHUP signal, for dynamic profiling: Profiling. (line 211) +* SIGINT signal (MS-Windows): Profiling. (line 214) +* signals, HUP/SIGHUP, for profiling: Profiling. (line 211) +* signals, INT/SIGINT (MS-Windows): Profiling. (line 214) +* signals, QUIT/SIGQUIT (MS-Windows): Profiling. (line 214) +* signals, USR1/SIGUSR1, for profiling: Profiling. (line 188) +* signature program: Signature Program. (line 6) +* SIGQUIT signal (MS-Windows): Profiling. (line 214) +* SIGUSR1 signal, for dynamic profiling: Profiling. (line 188) * silent debugger command: Debugger Execution Control. (line 10) -* sin() function: Numeric Functions. (line 75) +* sin: Numeric Functions. (line 75) +* sine: Numeric Functions. (line 75) * single precision floating-point: General Arithmetic. (line 21) -* single quote (') <1>: Quoting. (line 31) -* single quote (') <2>: Long. (line 33) * single quote ('): One-shot. (line 15) +* single quote (') in gawk command lines: Long. (line 33) +* single quote ('), in shell commands: Quoting. (line 31) * single quote ('), vs. apostrophe: Comments. (line 27) * single quote ('), with double quotes: Quoting. (line 53) * single-character fields: Single Character Fields. (line 6) +* single-step execution, in the debugger: Debugger Execution Control. + (line 43) * Skywalker, Luke: Undocumented. (line 6) * sleep utility: Alarm Program. (line 111) * sleep() extension function: Extension Sample Time. (line 23) * Solaris, POSIX-compliant awk: Other Versions. (line 96) +* sort array: String Functions. (line 32) +* sort array indices: String Functions. (line 32) * sort function, arrays, sorting: Array Sorting Functions. (line 6) * sort utility: Word Sorting. (line 50) @@ -32417,25 +32739,29 @@ Index * source code, mawk: Other Versions. (line 44) * source code, mixing: Options. (line 117) * source code, pawk: Other Versions. (line 78) +* source code, pawk (Python version): Other Versions. (line 124) * source code, QSE Awk: Other Versions. (line 130) * source code, QuikTrim Awk: Other Versions. (line 134) * source code, Solaris awk: Other Versions. (line 96) * source files, search path for: Igawk Program. (line 368) * sparse arrays: Array Intro. (line 70) * Spencer, Henry: Glossary. (line 12) +* split: String Functions. (line 313) +* split string into array: String Functions. (line 291) * split utility: Split Program. (line 6) -* split() function: String Functions. (line 312) * split() function, array elements, deleting: Delete. (line 61) * split.awk program: Split Program. (line 30) -* sprintf() function <1>: String Functions. (line 377) -* sprintf() function: OFMT. (line 15) +* sprintf <1>: String Functions. (line 378) +* sprintf: OFMT. (line 15) * sprintf() function, OFMT variable and: User-modified. (line 124) * sprintf() function, print/printf statements and: Round Function. (line 6) -* sqrt() function: Numeric Functions. (line 78) -* square brackets ([]): Regexp Operators. (line 55) -* srand() function: Numeric Functions. (line 82) -* Stallman, Richard <1>: Glossary. (line 305) +* sqrt: Numeric Functions. (line 78) +* square brackets ([]), regexp operator: Regexp Operators. (line 55) +* square root: Numeric Functions. (line 78) +* srand: Numeric Functions. (line 82) +* stack frame: Debugging Terms. (line 10) +* Stallman, Richard <1>: Glossary. (line 297) * Stallman, Richard <2>: Contributors. (line 23) * Stallman, Richard <3>: Acknowledgments. (line 18) * Stallman, Richard: Manual History. (line 6) @@ -32443,6 +32769,7 @@ Index * standard input <1>: Special FD. (line 6) * standard input: Read Terminal. (line 6) * standard output: Special FD. (line 6) +* starting the debugger: Debugger Invocation. (line 6) * stat() extension function: Extension Sample File Functions. (line 18) * statements, compound, control statements and: Statements. (line 10) @@ -32452,35 +32779,42 @@ Index (line 68) * stepi debugger command: Debugger Execution Control. (line 76) +* stop automatic display, in debugger: Viewing And Changing Data. + (line 80) * stream editors <1>: Simple Sed. (line 6) * stream editors: Field Splitting Summary. (line 46) -* strftime() function (gawk): Time Functions. (line 48) +* strftime: Time Functions. (line 48) * string constants: Scalar Constants. (line 15) * string constants, vs. regexp constants: Computed Regexps. (line 38) * string extraction (internationalization): String Extraction. (line 6) +* string length: String Functions. (line 164) * string operators: Concatenation. (line 8) +* string, regular expression match: String Functions. (line 204) +* string-manipulation functions: String Functions. (line 6) * string-matching operators: Regexp Usage. (line 19) +* string-translation functions: I18N Functions. (line 6) +* strings splitting, example: String Functions. (line 333) * strings, converting <1>: Bitwise Functions. (line 109) * strings, converting: Conversion. (line 6) +* strings, converting letter case: String Functions. (line 520) * strings, converting, numbers to: User-modified. (line 28) -* strings, empty, See null strings: Records. (line 107) +* strings, empty, See null strings: Records. (line 122) * strings, extracting: String Extraction. (line 6) * strings, for localization: Programmer i18n. (line 14) -* strings, length of: Scalar Constants. (line 20) +* strings, length limitations: Scalar Constants. (line 20) * strings, merging arrays into: Join Function. (line 6) * strings, null: Regexp Field Splitting. (line 43) * strings, numeric: Variable Typing. (line 6) -* strings, splitting: String Functions. (line 332) -* strtonum() function (gawk): String Functions. (line 384) +* strtonum: String Functions. (line 385) * strtonum() function (gawk), --non-decimal-data option and: Nondecimal Data. (line 36) -* sub() function <1>: String Functions. (line 405) -* sub() function: Using Constant Regexps. +* sub <1>: String Functions. (line 406) +* sub: Using Constant Regexps. (line 43) -* sub() function, arguments of: String Functions. (line 459) +* sub() function, arguments of: String Functions. (line 460) * sub() function, escape processing: Gory Details. (line 6) * subscript separators: User-modified. (line 156) * subscripts in arrays, multidimensional: Multidimensional. (line 10) @@ -32491,15 +32825,19 @@ Index * subscripts in arrays, uninitialized variables as: Uninitialized Subscripts. (line 6) * SUBSEP variable: User-modified. (line 156) -* SUBSEP variable, multidimensional arrays: Multidimensional. (line 16) -* substr() function: String Functions. (line 478) +* SUBSEP variable, and multidimensional arrays: Multidimensional. + (line 16) +* substitute in string: String Functions. (line 82) +* substr: String Functions. (line 479) +* substring: String Functions. (line 479) * Sumner, Andrew: Other Versions. (line 64) +* supplementary groups of gawk process: Auto-set. (line 243) * switch statement: Switch Statement. (line 6) * SYMTAB array: Auto-set. (line 283) * syntactic ambiguity: /= operator vs. /=.../ regexp constant: Assignment Ops. (line 147) -* system() function: I/O Functions. (line 72) -* systime() function (gawk): Time Functions. (line 65) +* system: I/O Functions. (line 72) +* systime: Time Functions. (line 66) * t debugger command (alias for tbreak): Breakpoint Control. (line 90) * tbreak debugger command: Breakpoint Control. (line 90) * Tcl: Library Names. (line 57) @@ -32507,7 +32845,8 @@ Index * TCP/IP, support for: Special Network. (line 6) * tee utility: Tee Program. (line 6) * tee.awk program: Tee Program. (line 26) -* terminating records: Records. (line 117) +* temporary breakpoint: Breakpoint Control. (line 90) +* terminating records: Records. (line 132) * testbits.awk program: Bitwise Functions. (line 70) * testext extension: Extension Sample API Tests. (line 6) @@ -32536,6 +32875,7 @@ Index * tilde (~), ~ operator <5>: Computed Regexps. (line 6) * tilde (~), ~ operator <6>: Case-sensitivity. (line 26) * tilde (~), ~ operator: Regexp Usage. (line 19) +* time functions: Time Functions. (line 6) * time, alarm clock example program: Alarm Program. (line 11) * time, localization and: Explaining gettext. (line 115) * time, managing: Getlocaltime Function. @@ -32543,15 +32883,18 @@ Index * time, retrieving: Time Functions. (line 17) * timeout, reading input: Read Timeout. (line 6) * timestamps: Time Functions. (line 6) -* timestamps, converting dates to: Time Functions. (line 75) +* timestamps, converting dates to: Time Functions. (line 76) * timestamps, formatted: Getlocaltime Function. (line 6) -* tolower() function: String Functions. (line 520) -* toupper() function: String Functions. (line 526) +* tolower: String Functions. (line 521) +* toupper: String Functions. (line 527) * tr utility: Translate Program. (line 6) * trace debugger command: Miscellaneous Debugger Commands. (line 108) +* traceback, display in debugger: Execution Stack. (line 13) +* translate string: I18N Functions. (line 22) * translate.awk program: Translate Program. (line 55) +* treating files, as single records: Records. (line 219) * troubleshooting, --non-decimal-data option: Options. (line 207) * troubleshooting, == operator: Comparison Operators. (line 37) @@ -32570,9 +32913,9 @@ Index * troubleshooting, gawk, fatal errors, function arguments: Calling Built-in. (line 16) * troubleshooting, getline function: File Checking. (line 25) -* troubleshooting, gsub()/sub() functions: String Functions. (line 469) -* troubleshooting, match() function: String Functions. (line 285) -* troubleshooting, patsplit() function: String Functions. (line 308) +* troubleshooting, gsub()/sub() functions: String Functions. (line 470) +* troubleshooting, match() function: String Functions. (line 286) +* troubleshooting, patsplit() function: String Functions. (line 309) * troubleshooting, print statement, omitting commas: Print Examples. (line 31) * troubleshooting, printing: Redirection. (line 118) @@ -32581,7 +32924,7 @@ Index * troubleshooting, regexp constants vs. string constants: Computed Regexps. (line 38) * troubleshooting, string concatenation: Concatenation. (line 26) -* troubleshooting, substr() function: String Functions. (line 496) +* troubleshooting, substr() function: String Functions. (line 497) * troubleshooting, system() function: I/O Functions. (line 94) * troubleshooting, typographical errors, global variables: Options. (line 98) @@ -32594,6 +32937,8 @@ Index * type conversion: Conversion. (line 21) * u debugger command (alias for until): Debugger Execution Control. (line 83) +* unassigned array elements: Reference to Elements. + (line 18) * undefined functions: Pass By Value/Reference. (line 71) * underscore (_), C macro: Explaining gettext. (line 70) @@ -32603,20 +32948,22 @@ Index * undisplay debugger command: Viewing And Changing Data. (line 80) * undocumented features: Undocumented. (line 6) -* Unicode: Glossary. (line 141) +* Unicode <1>: Glossary. (line 133) +* Unicode <2>: Ranges and Locales. (line 61) +* Unicode: Ordinal Functions. (line 45) * uninitialized variables, as array subscripts: Uninitialized Subscripts. (line 6) * uniq utility: Uniq Program. (line 6) * uniq.awk program: Uniq Program. (line 65) -* Unix: Glossary. (line 624) +* Unix: Glossary. (line 616) * Unix awk, backslashes in escape sequences: Escape Sequences. (line 124) * Unix awk, close() function and: Close Files And Pipes. (line 130) * Unix awk, password files, field separators and: Command Line Field Separator. - (line 72) + (line 64) * Unix, awk scripts and: Executable Scripts. (line 6) -* UNIXROOT variable, on OS/2 systems: PC Using. (line 17) +* UNIXROOT variable, on OS/2 systems: PC Using. (line 16) * unsigned integers: General Arithmetic. (line 15) * until debugger command: Debugger Execution Control. (line 83) @@ -32624,15 +32971,16 @@ Index (line 84) * up debugger command: Execution Stack. (line 33) * user database, reading: Passwd Functions. (line 6) -* user-defined, functions: User-defined. (line 6) -* user-defined, functions, counts: Profiling. (line 129) +* user-defined functions: User-defined. (line 6) +* user-defined, functions, counts, in a profile: Profiling. (line 137) * user-defined, variables: Variables. (line 6) * user-modifiable variables: User-modified. (line 6) * users, information about, printing: Id Program. (line 6) * users, information about, retrieving: Passwd Functions. (line 16) -* USR1 signal: Profiling. (line 181) +* USR1 signal, for dynamic profiling: Profiling. (line 188) * values, numeric: Basic Data Typing. (line 13) * values, string: Basic Data Typing. (line 13) +* variable assignments and input files: Other Arguments. (line 19) * variable typing: Typing and Comparison. (line 9) * variables <1>: Basic Data Typing. (line 6) @@ -32653,7 +33001,7 @@ Index * variables, global, for library functions: Library Names. (line 11) * variables, global, printing list of: Options. (line 93) * variables, initializing: Using Variables. (line 20) -* variables, local: Variable Scope. (line 6) +* variables, local to a function: Variable Scope. (line 6) * variables, names of: Arrays. (line 18) * variables, private: Library Names. (line 11) * variables, setting: Options. (line 32) @@ -32664,6 +33012,10 @@ Index * variables, uninitialized, as array subscripts: Uninitialized Subscripts. (line 6) * variables, user-defined: Variables. (line 6) +* version of gawk: Auto-set. (line 213) +* version of gawk extension API: Auto-set. (line 238) +* version of GNU MP library: Auto-set. (line 224) +* version of GNU MPFR library: Auto-set. (line 220) * vertical bar (|): Regexp Operators. (line 69) * vertical bar (|), | operator (I/O) <1>: Precedence. (line 65) * vertical bar (|), | operator (I/O): Getline/Pipe. (line 9) @@ -32687,12 +33039,13 @@ Index * warnings, issuing: Options. (line 182) * watch debugger command: Viewing And Changing Data. (line 67) +* watchpoint: Debugging Terms. (line 42) * wc utility: Wc Program. (line 6) * wc.awk program: Wc Program. (line 46) * Weinberger, Peter <1>: Contributors. (line 11) * Weinberger, Peter: History. (line 17) -* while statement <1>: While Statement. (line 6) -* while statement: Regexp Usage. (line 19) +* while statement: While Statement. (line 6) +* while statement, use of regexps in: Regexp Usage. (line 19) * whitespace, as field separators: Default Field Splitting. (line 6) * whitespace, functions, calling: Calling Built-in. (line 10) @@ -32713,16 +33066,16 @@ Index * writea() extension function: Extension Sample Read write array. (line 9) * xgettext utility: String Extraction. (line 13) +* xor: Bitwise Functions. (line 55) * XOR bitwise operation: Bitwise Functions. (line 6) -* xor() function (gawk): Bitwise Functions. (line 55) -* Yawitz, Efraim: Contributors. (line 126) +* Yawitz, Efraim: Contributors. (line 129) * Zaretskii, Eli <1>: Bugs. (line 70) * Zaretskii, Eli <2>: Contributors. (line 55) * Zaretskii, Eli: Acknowledgments. (line 60) * zero, negative vs. positive: Unexpected Results. (line 34) * zerofile.awk program: Empty Files. (line 21) * Zoulas, Christos: Contributors. (line 66) -* {} (braces): Profiling. (line 134) +* {} (braces): Profiling. (line 142) * {} (braces), actions and: Action Overview. (line 19) * {} (braces), statements, grouping: Statements. (line 10) * | (vertical bar): Regexp Operators. (line 69) @@ -32749,526 +33102,530 @@ Index Tag Table: -Node: Top1366 -Node: Foreword40856 -Node: Preface45201 -Ref: Preface-Footnote-148254 -Ref: Preface-Footnote-248350 -Node: History48582 -Node: Names50956 -Ref: Names-Footnote-152433 -Node: This Manual52505 -Ref: This Manual-Footnote-158279 -Node: Conventions58379 -Node: Manual History60535 -Ref: Manual History-Footnote-163983 -Ref: Manual History-Footnote-264024 -Node: How To Contribute64098 -Node: Acknowledgments65242 -Node: Getting Started69436 -Node: Running gawk71815 -Node: One-shot73001 -Node: Read Terminal74226 -Ref: Read Terminal-Footnote-175876 -Ref: Read Terminal-Footnote-276152 -Node: Long76323 -Node: Executable Scripts77699 -Ref: Executable Scripts-Footnote-179532 -Ref: Executable Scripts-Footnote-279634 -Node: Comments80181 -Node: Quoting82648 -Node: DOS Quoting87271 -Node: Sample Data Files87946 -Node: Very Simple90332 -Node: Two Rules94931 -Node: More Complex97078 -Ref: More Complex-Footnote-1100008 -Node: Statements/Lines100093 -Ref: Statements/Lines-Footnote-1104555 -Node: Other Features104820 -Node: When105748 -Node: Invoking Gawk107895 -Node: Command Line109358 -Node: Options110141 -Ref: Options-Footnote-1125536 -Node: Other Arguments125561 -Node: Naming Standard Input128219 -Node: Environment Variables129313 -Node: AWKPATH Variable129871 -Ref: AWKPATH Variable-Footnote-1132629 -Node: AWKLIBPATH Variable132889 -Node: Other Environment Variables133607 -Node: Exit Status136570 -Node: Include Files137245 -Node: Loading Shared Libraries140814 -Node: Obsolete142178 -Node: Undocumented142875 -Node: Regexp143117 -Node: Regexp Usage144506 -Node: Escape Sequences146532 -Node: Regexp Operators152201 -Ref: Regexp Operators-Footnote-1159581 -Ref: Regexp Operators-Footnote-2159728 -Node: Bracket Expressions159826 -Ref: table-char-classes161716 -Node: GNU Regexp Operators164239 -Node: Case-sensitivity167962 -Ref: Case-sensitivity-Footnote-1170930 -Ref: Case-sensitivity-Footnote-2171165 -Node: Leftmost Longest171273 -Node: Computed Regexps172474 -Node: Reading Files175811 -Node: Records177813 -Ref: Records-Footnote-1186901 -Node: Fields186938 -Ref: Fields-Footnote-1189971 -Node: Nonconstant Fields190057 -Node: Changing Fields192259 -Node: Field Separators198218 -Node: Default Field Splitting200920 -Node: Regexp Field Splitting202037 -Node: Single Character Fields205379 -Node: Command Line Field Separator206438 -Node: Full Line Fields209872 -Ref: Full Line Fields-Footnote-1210380 -Node: Field Splitting Summary210426 -Ref: Field Splitting Summary-Footnote-1213525 -Node: Constant Size213626 -Node: Splitting By Content218233 -Ref: Splitting By Content-Footnote-1221982 -Node: Multiple Line222022 -Ref: Multiple Line-Footnote-1227869 -Node: Getline228048 -Node: Plain Getline230264 -Node: Getline/Variable232359 -Node: Getline/File233506 -Node: Getline/Variable/File234847 -Ref: Getline/Variable/File-Footnote-1236446 -Node: Getline/Pipe236533 -Node: Getline/Variable/Pipe239232 -Node: Getline/Coprocess240339 -Node: Getline/Variable/Coprocess241591 -Node: Getline Notes242328 -Node: Getline Summary245115 -Ref: table-getline-variants245523 -Node: Read Timeout246435 -Ref: Read Timeout-Footnote-1250176 -Node: Command line directories250233 -Node: Printing250863 -Node: Print252494 -Node: Print Examples253831 -Node: Output Separators256615 -Node: OFMT258375 -Node: Printf259733 -Node: Basic Printf260639 -Node: Control Letters262178 -Node: Format Modifiers265990 -Node: Printf Examples271999 -Node: Redirection274714 -Node: Special Files281679 -Node: Special FD282212 -Ref: Special FD-Footnote-1285837 -Node: Special Network285911 -Node: Special Caveats286761 -Node: Close Files And Pipes287557 -Ref: Close Files And Pipes-Footnote-1294540 -Ref: Close Files And Pipes-Footnote-2294688 -Node: Expressions294838 -Node: Values295970 -Node: Constants296646 -Node: Scalar Constants297326 -Ref: Scalar Constants-Footnote-1298185 -Node: Nondecimal-numbers298367 -Node: Regexp Constants301367 -Node: Using Constant Regexps301842 -Node: Variables304897 -Node: Using Variables305552 -Node: Assignment Options307276 -Node: Conversion309148 -Ref: table-locale-affects314648 -Ref: Conversion-Footnote-1315272 -Node: All Operators315381 -Node: Arithmetic Ops316011 -Node: Concatenation318516 -Ref: Concatenation-Footnote-1321308 -Node: Assignment Ops321428 -Ref: table-assign-ops326416 -Node: Increment Ops327747 -Node: Truth Values and Conditions331181 -Node: Truth Values332264 -Node: Typing and Comparison333313 -Node: Variable Typing334106 -Ref: Variable Typing-Footnote-1338003 -Node: Comparison Operators338125 -Ref: table-relational-ops338535 -Node: POSIX String Comparison342083 -Ref: POSIX String Comparison-Footnote-1343039 -Node: Boolean Ops343177 -Ref: Boolean Ops-Footnote-1347255 -Node: Conditional Exp347346 -Node: Function Calls349078 -Node: Precedence352672 -Node: Locales356341 -Node: Patterns and Actions357430 -Node: Pattern Overview358484 -Node: Regexp Patterns360153 -Node: Expression Patterns360696 -Node: Ranges364381 -Node: BEGIN/END367347 -Node: Using BEGIN/END368109 -Ref: Using BEGIN/END-Footnote-1370840 -Node: I/O And BEGIN/END370946 -Node: BEGINFILE/ENDFILE373228 -Node: Empty376142 -Node: Using Shell Variables376458 -Node: Action Overview378743 -Node: Statements381100 -Node: If Statement382954 -Node: While Statement384453 -Node: Do Statement386497 -Node: For Statement387653 -Node: Switch Statement390805 -Node: Break Statement392902 -Node: Continue Statement394892 -Node: Next Statement396685 -Node: Nextfile Statement399075 -Node: Exit Statement401718 -Node: Built-in Variables404134 -Node: User-modified405229 -Ref: User-modified-Footnote-1413587 -Node: Auto-set413649 -Ref: Auto-set-Footnote-1427119 -Ref: Auto-set-Footnote-2427324 -Node: ARGC and ARGV427380 -Node: Arrays431231 -Node: Array Basics432736 -Node: Array Intro433562 -Node: Reference to Elements437879 -Node: Assigning Elements440149 -Node: Array Example440640 -Node: Scanning an Array442372 -Node: Controlling Scanning444686 -Ref: Controlling Scanning-Footnote-1449773 -Node: Delete450089 -Ref: Delete-Footnote-1452854 -Node: Numeric Array Subscripts452911 -Node: Uninitialized Subscripts455094 -Node: Multidimensional456721 -Node: Multiscanning459814 -Node: Arrays of Arrays461403 -Node: Functions466043 -Node: Built-in466862 -Node: Calling Built-in467940 -Node: Numeric Functions469928 -Ref: Numeric Functions-Footnote-1473760 -Ref: Numeric Functions-Footnote-2474117 -Ref: Numeric Functions-Footnote-3474165 -Node: String Functions474434 -Ref: String Functions-Footnote-1497354 -Ref: String Functions-Footnote-2497483 -Ref: String Functions-Footnote-3497731 -Node: Gory Details497818 -Ref: table-sub-escapes499497 -Ref: table-sub-posix-92500851 -Ref: table-sub-proposed502202 -Ref: table-posix-sub503556 -Ref: table-gensub-escapes505101 -Ref: Gory Details-Footnote-1506277 -Ref: Gory Details-Footnote-2506328 -Node: I/O Functions506479 -Ref: I/O Functions-Footnote-1513464 -Node: Time Functions513611 -Ref: Time Functions-Footnote-1524544 -Ref: Time Functions-Footnote-2524612 -Ref: Time Functions-Footnote-3524770 -Ref: Time Functions-Footnote-4524881 -Ref: Time Functions-Footnote-5524993 -Ref: Time Functions-Footnote-6525220 -Node: Bitwise Functions525486 -Ref: table-bitwise-ops526048 -Ref: Bitwise Functions-Footnote-1530269 -Node: Type Functions530453 -Node: I18N Functions531604 -Node: User-defined533231 -Node: Definition Syntax534035 -Ref: Definition Syntax-Footnote-1538945 -Node: Function Example539014 -Node: Function Caveats541608 -Node: Calling A Function542029 -Node: Variable Scope543144 -Node: Pass By Value/Reference546107 -Node: Return Statement549615 -Node: Dynamic Typing552596 -Node: Indirect Calls553527 -Node: Library Functions563212 -Ref: Library Functions-Footnote-1566725 -Ref: Library Functions-Footnote-2566868 -Node: Library Names567039 -Ref: Library Names-Footnote-1570510 -Ref: Library Names-Footnote-2570730 -Node: General Functions570816 -Node: Strtonum Function571844 -Node: Assert Function574774 -Node: Round Function578100 -Node: Cliff Random Function579643 -Node: Ordinal Functions580659 -Ref: Ordinal Functions-Footnote-1583731 -Ref: Ordinal Functions-Footnote-2583983 -Node: Join Function584192 -Ref: Join Function-Footnote-1585963 -Node: Getlocaltime Function586163 -Node: Readfile Function589904 -Node: Data File Management591743 -Node: Filetrans Function592375 -Node: Rewind Function596444 -Node: File Checking597831 -Node: Empty Files598925 -Node: Ignoring Assigns601155 -Node: Getopt Function602708 -Ref: Getopt Function-Footnote-1614011 -Node: Passwd Functions614214 -Ref: Passwd Functions-Footnote-1623189 -Node: Group Functions623277 -Node: Walking Arrays631361 -Node: Sample Programs633498 -Node: Running Examples634172 -Node: Clones634900 -Node: Cut Program636124 -Node: Egrep Program645969 -Ref: Egrep Program-Footnote-1653742 -Node: Id Program653852 -Node: Split Program657468 -Ref: Split Program-Footnote-1660987 -Node: Tee Program661115 -Node: Uniq Program663918 -Node: Wc Program671347 -Ref: Wc Program-Footnote-1675613 -Ref: Wc Program-Footnote-2675813 -Node: Miscellaneous Programs675905 -Node: Dupword Program677093 -Node: Alarm Program679124 -Node: Translate Program683931 -Ref: Translate Program-Footnote-1688318 -Ref: Translate Program-Footnote-2688566 -Node: Labels Program688700 -Ref: Labels Program-Footnote-1692071 -Node: Word Sorting692155 -Node: History Sorting696039 -Node: Extract Program697878 -Ref: Extract Program-Footnote-1705381 -Node: Simple Sed705509 -Node: Igawk Program708571 -Ref: Igawk Program-Footnote-1723728 -Ref: Igawk Program-Footnote-2723929 -Node: Anagram Program724067 -Node: Signature Program727135 -Node: Advanced Features728235 -Node: Nondecimal Data730121 -Node: Array Sorting731704 -Node: Controlling Array Traversal732401 -Node: Array Sorting Functions740685 -Ref: Array Sorting Functions-Footnote-1744554 -Node: Two-way I/O744748 -Ref: Two-way I/O-Footnote-1750180 -Node: TCP/IP Networking750250 -Node: Profiling753094 -Node: Internationalization760591 -Node: I18N and L10N762016 -Node: Explaining gettext762702 -Ref: Explaining gettext-Footnote-1767770 -Ref: Explaining gettext-Footnote-2767954 -Node: Programmer i18n768119 -Node: Translator i18n772321 -Node: String Extraction773114 -Ref: String Extraction-Footnote-1774075 -Node: Printf Ordering774161 -Ref: Printf Ordering-Footnote-1776945 -Node: I18N Portability777009 -Ref: I18N Portability-Footnote-1779458 -Node: I18N Example779521 -Ref: I18N Example-Footnote-1782159 -Node: Gawk I18N782231 -Node: Debugger782852 -Node: Debugging783823 -Node: Debugging Concepts784256 -Node: Debugging Terms786112 -Node: Awk Debugging788709 -Node: Sample Debugging Session789601 -Node: Debugger Invocation790121 -Node: Finding The Bug791453 -Node: List of Debugger Commands797941 -Node: Breakpoint Control799275 -Node: Debugger Execution Control802939 -Node: Viewing And Changing Data806299 -Node: Execution Stack809655 -Node: Debugger Info811122 -Node: Miscellaneous Debugger Commands815104 -Node: Readline Support820280 -Node: Limitations821111 -Node: Arbitrary Precision Arithmetic823363 -Ref: Arbitrary Precision Arithmetic-Footnote-1825012 -Node: General Arithmetic825160 -Node: Floating Point Issues826880 -Node: String Conversion Precision827761 -Ref: String Conversion Precision-Footnote-1829466 -Node: Unexpected Results829575 -Node: POSIX Floating Point Problems831728 -Ref: POSIX Floating Point Problems-Footnote-1835553 -Node: Integer Programming835591 -Node: Floating-point Programming837330 -Ref: Floating-point Programming-Footnote-1843661 -Ref: Floating-point Programming-Footnote-2843931 -Node: Floating-point Representation844195 -Node: Floating-point Context845360 -Ref: table-ieee-formats846199 -Node: Rounding Mode847583 -Ref: table-rounding-modes848062 -Ref: Rounding Mode-Footnote-1851077 -Node: Gawk and MPFR851256 -Node: Arbitrary Precision Floats852511 -Ref: Arbitrary Precision Floats-Footnote-1854954 -Node: Setting Precision855270 -Ref: table-predefined-precision-strings855956 -Node: Setting Rounding Mode858101 -Ref: table-gawk-rounding-modes858505 -Node: Floating-point Constants859692 -Node: Changing Precision861121 -Ref: Changing Precision-Footnote-1862518 -Node: Exact Arithmetic862692 -Node: Arbitrary Precision Integers865830 -Ref: Arbitrary Precision Integers-Footnote-1868848 -Node: Dynamic Extensions868995 -Node: Extension Intro870453 -Node: Plugin License871718 -Node: Extension Mechanism Outline872403 -Ref: load-extension872820 -Ref: load-new-function874298 -Ref: call-new-function875293 -Node: Extension API Description877308 -Node: Extension API Functions Introduction878521 -Node: General Data Types883387 -Ref: General Data Types-Footnote-1888989 -Node: Requesting Values889288 -Ref: table-value-types-returned890019 -Node: Constructor Functions890973 -Node: Registration Functions893993 -Node: Extension Functions894678 -Node: Exit Callback Functions896903 -Node: Extension Version String898152 -Node: Input Parsers898802 -Node: Output Wrappers908559 -Node: Two-way processors913069 -Node: Printing Messages915277 -Ref: Printing Messages-Footnote-1916354 -Node: Updating `ERRNO'916506 -Node: Accessing Parameters917245 -Node: Symbol Table Access918475 -Node: Symbol table by name918987 -Node: Symbol table by cookie920734 -Ref: Symbol table by cookie-Footnote-1924864 -Node: Cached values924927 -Ref: Cached values-Footnote-1928376 -Node: Array Manipulation928467 -Ref: Array Manipulation-Footnote-1929565 -Node: Array Data Types929604 -Ref: Array Data Types-Footnote-1932307 -Node: Array Functions932399 -Node: Flattening Arrays936165 -Node: Creating Arrays943017 -Node: Extension API Variables947742 -Node: Extension Versioning948378 -Node: Extension API Informational Variables950279 -Node: Extension API Boilerplate951365 -Node: Finding Extensions955169 -Node: Extension Example955729 -Node: Internal File Description956459 -Node: Internal File Ops960550 -Ref: Internal File Ops-Footnote-1972058 -Node: Using Internal File Ops972198 -Ref: Using Internal File Ops-Footnote-1974551 -Node: Extension Samples974817 -Node: Extension Sample File Functions976341 -Node: Extension Sample Fnmatch984826 -Node: Extension Sample Fork986552 -Node: Extension Sample Inplace987770 -Node: Extension Sample Ord989548 -Node: Extension Sample Readdir990384 -Node: Extension Sample Revout991916 -Node: Extension Sample Rev2way992509 -Node: Extension Sample Read write array993199 -Node: Extension Sample Readfile995082 -Node: Extension Sample API Tests995900 -Node: Extension Sample Time996425 -Node: gawkextlib997789 -Node: Language History1000570 -Node: V7/SVR3.11002163 -Node: SVR41004483 -Node: POSIX1005925 -Node: BTL1007311 -Node: POSIX/GNU1008045 -Node: Feature History1013644 -Node: Common Extensions1026608 -Node: Ranges and Locales1027920 -Ref: Ranges and Locales-Footnote-11032538 -Ref: Ranges and Locales-Footnote-21032565 -Ref: Ranges and Locales-Footnote-31032825 -Node: Contributors1033046 -Node: Installation1038191 -Node: Gawk Distribution1039085 -Node: Getting1039569 -Node: Extracting1040395 -Node: Distribution contents1042087 -Node: Unix Installation1047792 -Node: Quick Installation1048409 -Node: Additional Configuration Options1050853 -Node: Configuration Philosophy1052589 -Node: Non-Unix Installation1054943 -Node: PC Installation1055401 -Node: PC Binary Installation1056700 -Node: PC Compiling1058548 -Node: PC Testing1061492 -Node: PC Using1062668 -Node: Cygwin1066853 -Node: MSYS1067853 -Node: VMS Installation1068367 -Node: VMS Compilation1069131 -Ref: VMS Compilation-Footnote-11070746 -Node: VMS Dynamic Extensions1070804 -Node: VMS Installation Details1072177 -Node: VMS Running1074424 -Node: VMS GNV1077258 -Node: VMS Old Gawk1077981 -Node: Bugs1078451 -Node: Other Versions1082369 -Node: Notes1088453 -Node: Compatibility Mode1089253 -Node: Additions1090036 -Node: Accessing The Source1090963 -Node: Adding Code1092403 -Node: New Ports1098448 -Node: Derived Files1102583 -Ref: Derived Files-Footnote-11107904 -Ref: Derived Files-Footnote-21107938 -Ref: Derived Files-Footnote-31108538 -Node: Future Extensions1108636 -Node: Implementation Limitations1109219 -Node: Extension Design1110471 -Node: Old Extension Problems1111625 -Ref: Old Extension Problems-Footnote-11113133 -Node: Extension New Mechanism Goals1113190 -Ref: Extension New Mechanism Goals-Footnote-11116555 -Node: Extension Other Design Decisions1116741 -Node: Extension Future Growth1118847 -Node: Old Extension Mechanism1119683 -Node: Basic Concepts1121423 -Node: Basic High Level1122104 -Ref: figure-general-flow1122375 -Ref: figure-process-flow1122974 -Ref: Basic High Level-Footnote-11126203 -Node: Basic Data Typing1126388 -Node: Glossary1129743 -Node: Copying1155205 -Node: GNU Free Documentation License1192762 -Node: Index1217899 +Node: Top1292 +Node: Foreword40821 +Node: Preface45166 +Ref: Preface-Footnote-148219 +Ref: Preface-Footnote-248315 +Node: History48547 +Node: Names50921 +Ref: Names-Footnote-152398 +Node: This Manual52470 +Ref: This Manual-Footnote-158244 +Node: Conventions58344 +Node: Manual History60500 +Ref: Manual History-Footnote-163948 +Ref: Manual History-Footnote-263989 +Node: How To Contribute64063 +Node: Acknowledgments65207 +Node: Getting Started69401 +Node: Running gawk71780 +Node: One-shot72966 +Node: Read Terminal74191 +Ref: Read Terminal-Footnote-175841 +Ref: Read Terminal-Footnote-276117 +Node: Long76288 +Node: Executable Scripts77664 +Ref: Executable Scripts-Footnote-179497 +Ref: Executable Scripts-Footnote-279599 +Node: Comments80146 +Node: Quoting82613 +Node: DOS Quoting87236 +Node: Sample Data Files87911 +Node: Very Simple90426 +Node: Two Rules95077 +Node: More Complex96975 +Ref: More Complex-Footnote-199905 +Node: Statements/Lines99990 +Ref: Statements/Lines-Footnote-1104453 +Node: Other Features104718 +Node: When105646 +Node: Invoking Gawk107793 +Node: Command Line109256 +Node: Options110039 +Ref: Options-Footnote-1125417 +Node: Other Arguments125442 +Node: Naming Standard Input128100 +Node: Environment Variables129194 +Node: AWKPATH Variable129752 +Ref: AWKPATH Variable-Footnote-1132533 +Ref: AWKPATH Variable-Footnote-2132578 +Node: AWKLIBPATH Variable132838 +Node: Other Environment Variables133556 +Node: Exit Status136519 +Node: Include Files137194 +Node: Loading Shared Libraries140763 +Node: Obsolete142127 +Node: Undocumented142824 +Node: Regexp143066 +Node: Regexp Usage144455 +Node: Escape Sequences146480 +Node: Regexp Operators152149 +Ref: Regexp Operators-Footnote-1159529 +Ref: Regexp Operators-Footnote-2159676 +Node: Bracket Expressions159774 +Ref: table-char-classes161664 +Node: GNU Regexp Operators164187 +Node: Case-sensitivity167910 +Ref: Case-sensitivity-Footnote-1170878 +Ref: Case-sensitivity-Footnote-2171113 +Node: Leftmost Longest171221 +Node: Computed Regexps172422 +Node: Reading Files175759 +Node: Records177761 +Ref: Records-Footnote-1187284 +Node: Fields187321 +Ref: Fields-Footnote-1190277 +Node: Nonconstant Fields190363 +Node: Changing Fields192569 +Node: Field Separators198528 +Node: Default Field Splitting201230 +Node: Regexp Field Splitting202347 +Node: Single Character Fields205689 +Node: Command Line Field Separator206748 +Node: Full Line Fields210090 +Ref: Full Line Fields-Footnote-1210598 +Node: Field Splitting Summary210644 +Ref: Field Splitting Summary-Footnote-1213743 +Node: Constant Size213844 +Node: Splitting By Content218451 +Ref: Splitting By Content-Footnote-1222200 +Node: Multiple Line222240 +Ref: Multiple Line-Footnote-1228087 +Node: Getline228266 +Node: Plain Getline230482 +Node: Getline/Variable232577 +Node: Getline/File233724 +Node: Getline/Variable/File235065 +Ref: Getline/Variable/File-Footnote-1236664 +Node: Getline/Pipe236751 +Node: Getline/Variable/Pipe239450 +Node: Getline/Coprocess240557 +Node: Getline/Variable/Coprocess241809 +Node: Getline Notes242546 +Node: Getline Summary245333 +Ref: table-getline-variants245741 +Node: Read Timeout246653 +Ref: Read Timeout-Footnote-1250394 +Node: Command line directories250451 +Node: Printing251081 +Node: Print252712 +Node: Print Examples254049 +Node: Output Separators256833 +Node: OFMT258849 +Node: Printf260207 +Node: Basic Printf261113 +Node: Control Letters262652 +Node: Format Modifiers266464 +Node: Printf Examples272473 +Node: Redirection275185 +Node: Special Files282159 +Node: Special FD282692 +Ref: Special FD-Footnote-1286317 +Node: Special Network286391 +Node: Special Caveats287241 +Node: Close Files And Pipes288037 +Ref: Close Files And Pipes-Footnote-1295020 +Ref: Close Files And Pipes-Footnote-2295168 +Node: Expressions295318 +Node: Values296450 +Node: Constants297126 +Node: Scalar Constants297806 +Ref: Scalar Constants-Footnote-1298665 +Node: Nondecimal-numbers298847 +Node: Regexp Constants301847 +Node: Using Constant Regexps302322 +Node: Variables305377 +Node: Using Variables306032 +Node: Assignment Options307756 +Node: 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+Ref: Wc Program-Footnote-1676545 +Ref: Wc Program-Footnote-2676745 +Node: Miscellaneous Programs676837 +Node: Dupword Program678025 +Node: Alarm Program680056 +Node: Translate Program684863 +Ref: Translate Program-Footnote-1689250 +Ref: Translate Program-Footnote-2689498 +Node: Labels Program689632 +Ref: Labels Program-Footnote-1693003 +Node: Word Sorting693087 +Node: History Sorting696971 +Node: Extract Program698810 +Ref: Extract Program-Footnote-1706313 +Node: Simple Sed706441 +Node: Igawk Program709503 +Ref: Igawk Program-Footnote-1724660 +Ref: Igawk Program-Footnote-2724861 +Node: Anagram Program724999 +Node: Signature Program728067 +Node: Advanced Features729167 +Node: Nondecimal Data731053 +Node: Array Sorting732636 +Node: Controlling Array Traversal733333 +Node: Array Sorting Functions741617 +Ref: Array Sorting Functions-Footnote-1745486 +Node: Two-way I/O745680 +Ref: Two-way I/O-Footnote-1751112 +Node: TCP/IP Networking751194 +Node: Profiling754038 +Node: Internationalization761541 +Node: I18N and L10N762966 +Node: Explaining gettext763652 +Ref: Explaining gettext-Footnote-1768720 +Ref: Explaining gettext-Footnote-2768904 +Node: Programmer i18n769069 +Node: Translator i18n773271 +Node: String Extraction774065 +Ref: String Extraction-Footnote-1775026 +Node: Printf Ordering775112 +Ref: Printf Ordering-Footnote-1777894 +Node: I18N Portability777958 +Ref: I18N Portability-Footnote-1780407 +Node: I18N Example780470 +Ref: I18N Example-Footnote-1783108 +Node: Gawk I18N783180 +Node: Debugger783801 +Node: Debugging784772 +Node: Debugging Concepts785205 +Node: Debugging Terms787061 +Node: Awk Debugging789658 +Node: Sample Debugging Session790550 +Node: Debugger Invocation791070 +Node: Finding The Bug792403 +Node: List of Debugger Commands798890 +Node: Breakpoint Control800224 +Node: Debugger Execution Control803888 +Node: Viewing And Changing Data807248 +Node: Execution Stack810604 +Node: Debugger Info812071 +Node: Miscellaneous Debugger Commands816053 +Node: Readline Support821229 +Node: Limitations822060 +Node: Arbitrary Precision Arithmetic824312 +Ref: Arbitrary Precision Arithmetic-Footnote-1825961 +Node: General Arithmetic826109 +Node: Floating Point Issues827829 +Node: String Conversion Precision828710 +Ref: String Conversion Precision-Footnote-1830415 +Node: Unexpected Results830524 +Node: POSIX Floating Point Problems832677 +Ref: POSIX Floating Point Problems-Footnote-1836502 +Node: Integer Programming836540 +Node: Floating-point Programming838279 +Ref: Floating-point Programming-Footnote-1844610 +Ref: Floating-point Programming-Footnote-2844880 +Node: Floating-point Representation845144 +Node: Floating-point Context846309 +Ref: table-ieee-formats847148 +Node: Rounding Mode848532 +Ref: table-rounding-modes849011 +Ref: Rounding Mode-Footnote-1852026 +Node: Gawk and MPFR852205 +Node: Arbitrary Precision Floats853616 +Ref: Arbitrary Precision Floats-Footnote-1856059 +Node: Setting Precision856375 +Ref: table-predefined-precision-strings857061 +Node: Setting Rounding Mode859206 +Ref: table-gawk-rounding-modes859610 +Node: Floating-point Constants860797 +Node: Changing Precision862226 +Ref: Changing Precision-Footnote-1863623 +Node: Exact Arithmetic863797 +Node: Arbitrary Precision Integers866935 +Ref: Arbitrary Precision Integers-Footnote-1869950 +Node: Dynamic Extensions870097 +Node: Extension Intro871555 +Node: Plugin License872820 +Node: Extension Mechanism Outline873505 +Ref: load-extension873922 +Ref: load-new-function875400 +Ref: call-new-function876395 +Node: Extension API Description878410 +Node: Extension API Functions Introduction879697 +Node: General Data Types884624 +Ref: General Data Types-Footnote-1890319 +Node: Requesting Values890618 +Ref: table-value-types-returned891355 +Node: Memory Allocation Functions892309 +Ref: Memory Allocation Functions-Footnote-1895055 +Node: Constructor Functions895151 +Node: Registration Functions896909 +Node: Extension Functions897594 +Node: Exit Callback Functions899896 +Node: Extension Version String901145 +Node: Input Parsers901795 +Node: Output Wrappers911552 +Node: Two-way processors916062 +Node: Printing Messages918270 +Ref: Printing Messages-Footnote-1919347 +Node: Updating `ERRNO'919499 +Node: Accessing Parameters920238 +Node: Symbol Table Access921468 +Node: Symbol table by name921982 +Node: Symbol table by cookie923958 +Ref: Symbol table by cookie-Footnote-1928090 +Node: Cached values928153 +Ref: Cached values-Footnote-1931643 +Node: Array Manipulation931734 +Ref: Array Manipulation-Footnote-1932832 +Node: Array Data Types932871 +Ref: Array Data Types-Footnote-1935574 +Node: Array Functions935666 +Node: Flattening Arrays939502 +Node: Creating Arrays946354 +Node: Extension API Variables951079 +Node: Extension Versioning951715 +Node: Extension API Informational Variables953616 +Node: Extension API Boilerplate954702 +Node: Finding Extensions958506 +Node: Extension Example959066 +Node: Internal File Description959796 +Node: Internal File Ops963887 +Ref: Internal File Ops-Footnote-1975396 +Node: Using Internal File Ops975536 +Ref: Using Internal File Ops-Footnote-1977889 +Node: Extension Samples978155 +Node: Extension Sample File Functions979679 +Node: Extension Sample Fnmatch988164 +Node: Extension Sample Fork989933 +Node: Extension Sample Inplace991146 +Node: Extension Sample Ord992924 +Node: Extension Sample Readdir993760 +Node: Extension Sample Revout995292 +Node: Extension Sample Rev2way995885 +Node: Extension Sample Read write array996575 +Node: Extension Sample Readfile998458 +Node: Extension Sample API Tests999558 +Node: Extension Sample Time1000083 +Node: gawkextlib1001447 +Node: Language History1004228 +Node: V7/SVR3.11005821 +Node: SVR41008141 +Node: POSIX1009583 +Node: BTL1010969 +Node: POSIX/GNU1011703 +Node: Feature History1017302 +Node: Common Extensions1030278 +Node: Ranges and Locales1031590 +Ref: Ranges and Locales-Footnote-11036207 +Ref: Ranges and Locales-Footnote-21036234 +Ref: Ranges and Locales-Footnote-31036468 +Node: Contributors1036689 +Node: Installation1042070 +Node: Gawk Distribution1042964 +Node: Getting1043448 +Node: Extracting1044274 +Node: Distribution contents1045966 +Node: Unix Installation1051671 +Node: Quick Installation1052288 +Node: Additional Configuration Options1054734 +Node: Configuration Philosophy1056470 +Node: Non-Unix Installation1058824 +Node: PC Installation1059282 +Node: PC Binary Installation1060581 +Node: PC Compiling1062429 +Node: PC Testing1065373 +Node: PC Using1066549 +Node: Cygwin1070717 +Node: MSYS1071526 +Node: VMS Installation1072040 +Node: VMS Compilation1072804 +Ref: VMS Compilation-Footnote-11074056 +Node: VMS Dynamic Extensions1074114 +Node: VMS Installation Details1075487 +Node: VMS Running1077738 +Node: VMS GNV1080572 +Node: VMS Old Gawk1081295 +Node: Bugs1081765 +Node: Other Versions1085683 +Node: Notes1091767 +Node: Compatibility Mode1092567 +Node: Additions1093350 +Node: Accessing The Source1094277 +Node: Adding Code1095717 +Node: New Ports1101762 +Node: Derived Files1105897 +Ref: Derived Files-Footnote-11111218 +Ref: Derived Files-Footnote-21111252 +Ref: Derived Files-Footnote-31111852 +Node: Future Extensions1111950 +Node: Implementation Limitations1112533 +Node: Extension Design1113785 +Node: Old Extension Problems1114939 +Ref: Old Extension Problems-Footnote-11116447 +Node: Extension New Mechanism Goals1116504 +Ref: Extension New Mechanism Goals-Footnote-11119869 +Node: Extension Other Design Decisions1120055 +Node: Extension Future Growth1122161 +Node: Old Extension Mechanism1122997 +Node: Basic Concepts1124737 +Node: Basic High Level1125418 +Ref: figure-general-flow1125690 +Ref: figure-process-flow1126289 +Ref: Basic High Level-Footnote-11129518 +Node: Basic Data Typing1129703 +Node: Glossary1133058 +Node: Copying1158289 +Node: GNU Free Documentation License1195845 +Node: Index1220981 End Tag Table diff --git a/doc/gawk.texi b/doc/gawk.texi index 0d780286..539ea53d 100644 --- a/doc/gawk.texi +++ b/doc/gawk.texi @@ -40,9 +40,9 @@ @c applies to and all the info about who's publishing this edition @c These apply across the board. -@set UPDATE-MONTH February, 2014 +@set UPDATE-MONTH April, 2014 @set VERSION 4.1 -@set PATCHLEVEL 0 +@set PATCHLEVEL 1 @set FSF @@ -116,11 +116,19 @@ @end ifnottex @ifnottex +@ifnotdocbook @macro ii{text} @i{\text\} @end macro +@end ifnotdocbook @end ifnottex +@ifdocbook +@macro ii{text} +@inlineraw{docbook,<lineannotation>\text\</lineannotation>} +@end macro +@end ifdocbook + @c For HTML, spell out email addresses, to avoid problems with @c address harvesters for spammers. @ifhtml @@ -134,9 +142,36 @@ @end macro @end ifnothtml +@c Indexing macros +@ifinfo + +@macro cindexawkfunc{name} +@cindex @code{\name\} +@end macro + +@macro cindexgawkfunc{name} +@cindex @code{\name\} +@end macro + +@end ifinfo + +@ifnotinfo + +@macro cindexawkfunc{name} +@cindex @code{\name\()} function +@end macro + +@macro cindexgawkfunc{name} +@cindex @code{\name\()} function (@command{gawk}) +@end macro +@end ifnotinfo + @ignore Some comments on the layout for TeX. 1. Use at least texinfo.tex 2014-01-30.15 +2. When using @docbook, if the last line is part of a paragraph, end +it with a space and @c so that the lines won't run together. This is a +quirk of the language / makeinfo, and isn't going to change. @end ignore @c merge the function and variable indexes into the concept index @@ -152,6 +187,10 @@ Some comments on the layout for TeX. @syncodeindex fn cp @syncodeindex vr cp @end ifxml +@ifdocbook +@synindex fn cp +@synindex vr cp +@end ifdocbook @c If "finalout" is commented out, the printed output will show @c black boxes that mark lines that are too long. Thus, it is @@ -163,10 +202,26 @@ Some comments on the layout for TeX. @end iftex @copying -Copyright @copyright{} 1989, 1991, 1992, 1993, 1996, 1997, 1998, 1999, -2000, 2001, 2002, 2003, 2004, 2005, 2007, 2009, 2010, 2011, 2012, 2013, -2014 +@docbook +<para>Published by:</para> + +<literallayout class="normal">Free Software Foundation +51 Franklin Street, Fifth Floor +Boston, MA 02110-1301 USA +Phone: +1-617-542-5942 +Fax: +1-617-542-2652 +Email: <email>gnu@@gnu.org</email> +URL: <ulink url="http://www.gnu.org">http://www.gnu.org/</ulink></literallayout> + +<literallayout class="normal">Copyright © 1989, 1991, 1992, 1993, 1996–2005, 2007, 2009–2014 Free Software Foundation, Inc. +All Rights Reserved.</literallayout> +@end docbook + +@ifnotdocbook +Copyright @copyright{} 1989, 1991, 1992, 1993, 1996--2005, 2007, 2009--2014 @* +Free Software Foundation, Inc. +@end ifnotdocbook @sp 2 This is Edition @value{EDITION} of @cite{@value{TITLE}: @value{SUBTITLE}}, @@ -214,6 +269,7 @@ supports it in developing GNU and promoting software freedom.'' @subtitle @value{UPDATE-MONTH} @author Arnold D. Robbins +@ifnotdocbook @c Include the Distribution inside the titlepage environment so @c that headings are turned off. Headings on and off do not work. @@ -238,6 +294,7 @@ URL: @uref{http://www.gnu.org/} @* ISBN 1-882114-28-0 @* @sp 2 @insertcopying +@end ifnotdocbook @end titlepage @c Thanks to Bob Chassell for directions on doing dedications. @@ -262,6 +319,18 @@ ISBN 1-882114-28-0 @* @headings on @end iftex +@docbook +<dedication> +<simplelist> +<member>To Miriam, for making me complete.</member> +<member>To Chana, for the joy you bring us.</member> +<member>To Rivka, for the exponential increase.</member> +<member>To Nachum, for the added dimension.</member> +<member>To Malka, for the new beginning.</member> +</simplelist> +</dedication> +@end docbook + @iftex @headings off @evenheading @thispage@ @ @ @strong{@value{TITLE}} @| @| @@ -270,6 +339,7 @@ ISBN 1-882114-28-0 @* @ifnottex @ifnotxml +@ifnotdocbook @node Top @top General Introduction @c Preface node should come right after the Top @@ -281,6 +351,7 @@ particular records in a file and perform operations upon them. @insertcopying +@end ifnotdocbook @end ifnotxml @end ifnottex @@ -742,6 +813,7 @@ particular records in a file and perform operations upon them. * Extension API Functions Introduction:: Introduction to the API functions. * General Data Types:: The data types. * Requesting Values:: How to get a value. +* Memory Allocation Functions:: Functions for allocating memory. * Constructor Functions:: Functions for creating values. * Registration Functions:: Functions to register things with @command{gawk}. @@ -804,7 +876,8 @@ particular records in a file and perform operations upon them. version of @command{awk}. * POSIX/GNU:: The extensions in @command{gawk} not in POSIX @command{awk}. -* Feature History:: The history of the features in @command{gawk}. +* Feature History:: The history of the features in + @command{gawk}. * Common Extensions:: Common Extensions Summary. * Ranges and Locales:: How locales used to affect regexp ranges. @@ -976,21 +1049,37 @@ and the AWK prototype becomes the product. The new @command{pgawk} (profiling @command{gawk}), produces program execution counts. I recently experimented with an algorithm that for -@math{n} lines of input, exhibited +@ifnotdocbook +@math{n} +@end ifnotdocbook +@ifdocbook +@i{n} +@end ifdocbook +lines of input, exhibited @tex $\sim\! Cn^2$ @end tex @ifnottex +@ifnotdocbook ~ C n^2 +@end ifnotdocbook @end ifnottex +@docbook +<emphasis>∼ Cn<superscript>2</superscript></emphasis> @c +@end docbook performance, while theory predicted @tex $\sim\! Cn\log n$ @end tex @ifnottex +@ifnotdocbook ~ C n log n +@end ifnotdocbook @end ifnottex +@docbook +<emphasis>∼ Cn log n</emphasis> @c +@end docbook behavior. A few minutes poring over the @file{awkprof.out} profile pinpointed the problem to a single line of code. @command{pgawk} is a welcome addition to @@ -1000,6 +1089,7 @@ Arnold has distilled over a decade of experience writing and using AWK programs, and developing @command{gawk}, into this book. If you use AWK or want to learn how, then read this book. +@cindex Brennan, Michael @display Michael Brennan Author of @command{mawk} @@ -1024,6 +1114,7 @@ Such jobs are often easier with @command{awk}. The @command{awk} utility interprets a special-purpose programming language that makes it easy to handle simple data-reformatting jobs. +@cindex Brian Kernighan's @command{awk} The GNU implementation of @command{awk} is called @command{gawk}; if you invoke it with the proper options or environment variables (@pxref{Options}), it is fully @@ -1774,7 +1865,7 @@ significant editorial help for this @value{DOCUMENT} for the 3.1 release of @command{gawk}. @end quotation -@cindex Beebe, Nelson +@cindex Beebe, Nelson H.F.@: @cindex Buening, Andreas @cindex Collado, Manuel @cindex Colombo, Antonio @@ -2067,11 +2158,11 @@ $ @kbd{awk "BEGIN @{ print \"Don't Panic!\" @}"} @print{} Don't Panic! @end example -@cindex quoting -@cindex double quote (@code{"}) -@cindex @code{"} (double quote) -@cindex @code{\} (backslash) -@cindex backslash (@code{\}) +@cindex shell quoting, double quote +@cindex double quote (@code{"}) in shell commands +@cindex @code{"} (double quote) in shell commands +@cindex @code{\} (backslash) in shell commands +@cindex backslash (@code{\}) in shell commands This program does not read any input. The @samp{\} before each of the inner double quotes is necessary because of the shell's quoting rules---in particular because it mixes both single quotes and @@ -2111,8 +2202,7 @@ awk -f @var{source-file} @var{input-file1} @var{input-file2} @dots{} @end example @cindex @option{-f} option -@cindex command line, options -@cindex options, command-line +@cindex command line, option @option{-f} The @option{-f} instructs the @command{awk} utility to get the @command{awk} program from the file @var{source-file}. Any file name can be used for @var{source-file}. For example, you could put the program: @@ -2135,7 +2225,7 @@ does the same thing as this one: awk "BEGIN @{ print \"Don't Panic!\" @}" @end example -@cindex quoting +@cindex quoting in @command{gawk} command lines @noindent This was explained earlier (@pxref{Read Terminal}). @@ -2146,9 +2236,9 @@ program did not have single quotes around it. The quotes are only needed for programs that are provided on the @command{awk} command line. @c STARTOFRANGE sq1x -@cindex single quote (@code{'}) +@cindex single quote (@code{'}) in @command{gawk} command lines @c STARTOFRANGE qs2x -@cindex @code{'} (single quote) +@cindex @code{'} (single quote) in @command{gawk} command lines If you want to clearly identify your @command{awk} program files as such, you can add the extension @file{.awk} to the file name. This doesn't affect the execution of the @command{awk} program but it does make @@ -2297,7 +2387,7 @@ programs, but this usually isn't very useful; the purpose of a comment is to help you or another person understand the program when reading it at a later time. -@cindex quoting +@cindex quoting, for small awk programs @cindex single quote (@code{'}), vs.@: apostrophe @cindex @code{'} (single quote), vs.@: apostrophe @quotation CAUTION @@ -2338,7 +2428,7 @@ The next @value{SUBSECTION} describes the shell's quoting rules. @node Quoting @subsection Shell-Quoting Issues -@cindex quoting, rules for +@cindex shell quoting, rules for @menu * DOS Quoting:: Quoting in Windows Batch Files. @@ -2373,10 +2463,10 @@ that character. The shell removes the backslash and passes the quoted character on to the command. @item -@cindex @code{\} (backslash) -@cindex backslash (@code{\}) -@cindex single quote (@code{'}) -@cindex @code{'} (single quote) +@cindex @code{\} (backslash), in shell commands +@cindex backslash (@code{\}), in shell commands +@cindex single quote (@code{'}), in shell commands +@cindex @code{'} (single quote), in shell commands Single quotes protect everything between the opening and closing quotes. The shell does no interpretation of the quoted text, passing it on verbatim to the command. @@ -2386,8 +2476,8 @@ Refer back to for an example of what happens if you try. @item -@cindex double quote (@code{"}) -@cindex @code{"} (double quote) +@cindex double quote (@code{"}), in shell commands +@cindex @code{"} (double quote), in shell commands Double quotes protect most things between the opening and closing quotes. The shell does at least variable and command substitution on the quoted text. Different shells may do additional kinds of processing on double-quoted text. @@ -2424,7 +2514,7 @@ awk -F "" '@var{program}' @var{files} # correct @end example @noindent -@cindex null strings, quoting and +@cindex null strings in @command{gawk} arguments, quoting and Don't use this: @example @@ -2437,7 +2527,7 @@ as the value of @code{FS}, and the first file name as the text of the program! This results in syntax errors at best, and confusing behavior at worst. @end itemize -@cindex quoting, tricks for +@cindex quoting in @command{gawk} command lines, tricks for Mixing single and double quotes is difficult. You have to resort to shell quoting tricks, like this: @@ -2552,40 +2642,39 @@ gawk "@{ print \"\042\" $0 \"\042\" @}" @var{file} @c For gawk >= 4.0, update these data files. No-one has such slow modems! @cindex input files, examples -@cindex @code{BBS-list} file +@cindex @code{mail-list} file Many of the examples in this @value{DOCUMENT} take their input from two sample -data files. The first, @file{BBS-list}, represents a list of -computer bulletin board systems together with information about those systems. +data files. The first, @file{mail-list}, represents a list of peoples' names +together with their email addresses and information about those people. The second data file, called @file{inventory-shipped}, contains information about monthly shipments. In both files, each line is considered to be one @dfn{record}. -In the data file @file{BBS-list}, each record contains the name of a computer -bulletin board, its phone number, the board's baud rate(s), and a code for -the number of hours it is operational. An @samp{A} in the last column -means the board operates 24 hours a day. A @samp{B} in the last -column means the board only operates on evening and weekend hours. -A @samp{C} means the board operates only on weekends: +In the data file @file{mail-list}, each record contains the name of a person, +his/her phone number, his/her email-address, and a code for their relationship +with the author of the list. An @samp{A} in the last column +means that the person is an acquaintance. An @samp{F} in the last +column means that the person is a friend. +An @samp{R} means that the person is a relative: -@c 2e: Update the baud rates to reflect today's faster modems @example @c system if test ! -d eg ; then mkdir eg ; fi @c system if test ! -d eg/lib ; then mkdir eg/lib ; fi @c system if test ! -d eg/data ; then mkdir eg/data ; fi @c system if test ! -d eg/prog ; then mkdir eg/prog ; fi @c system if test ! -d eg/misc ; then mkdir eg/misc ; fi -@c file eg/data/BBS-list -aardvark 555-5553 1200/300 B -alpo-net 555-3412 2400/1200/300 A -barfly 555-7685 1200/300 A -bites 555-1675 2400/1200/300 A -camelot 555-0542 300 C -core 555-2912 1200/300 C -fooey 555-1234 2400/1200/300 B -foot 555-6699 1200/300 B -macfoo 555-6480 1200/300 A -sdace 555-3430 2400/1200/300 A -sabafoo 555-2127 1200/300 C +@c file eg/data/mail-list +Amelia 555-5553 amelia.zodiacusque@@gmail.com F +Anthony 555-3412 anthony.asserturo@@hotmail.com A +Becky 555-7685 becky.algebrarum@@gmail.com A +Bill 555-1675 bill.drowning@@hotmail.com A +Broderick 555-0542 broderick.aliquotiens@@yahoo.com R +Camilla 555-2912 camilla.infusarum@@skynet.be R +Fabius 555-1234 fabius.undevicesimus@@ucb.edu F +Julie 555-6699 julie.perscrutabor@@skeeve.com F +Martin 555-6480 martin.codicibus@@hotmail.com A +Samuel 555-3430 samuel.lanceolis@@shu.edu A +Jean-Paul 555-2127 jeanpaul.campanorum@@nyu.edu R @c endfile @end example @@ -2627,23 +2716,23 @@ in the directory @file{awklib/eg/data}. @section Some Simple Examples The following command runs a simple @command{awk} program that searches the -input file @file{BBS-list} for the character string @samp{foo} (a +input file @file{mail-list} for the character string @samp{li} (a grouping of characters is usually called a @dfn{string}; the term @dfn{string} is based on similar usage in English, such as ``a string of pearls,'' or ``a string of cars in a train''): @example -awk '/foo/ @{ print $0 @}' BBS-list +awk '/li/ @{ print $0 @}' mail-list @end example @noindent -When lines containing @samp{foo} are found, they are printed because +When lines containing @samp{li} are found, they are printed because @w{@samp{print $0}} means print the current line. (Just @samp{print} by itself means the same thing, so we could have written that instead.) -You will notice that slashes (@samp{/}) surround the string @samp{foo} -in the @command{awk} program. The slashes indicate that @samp{foo} +You will notice that slashes (@samp{/}) surround the string @samp{li} +in the @command{awk} program. The slashes indicate that @samp{li} is the pattern to search for. This type of pattern is called a @dfn{regular expression}, which is covered in more detail later (@pxref{Regexp}). @@ -2655,11 +2744,11 @@ interpret any of it as special shell characters. Here is what this program prints: @example -$ @kbd{awk '/foo/ @{ print $0 @}' BBS-list} -@print{} fooey 555-1234 2400/1200/300 B -@print{} foot 555-6699 1200/300 B -@print{} macfoo 555-6480 1200/300 A -@print{} sabafoo 555-2127 1200/300 C +$ @kbd{awk '/li/ @{ print $0 @}' mail-list} +@print{} Amelia 555-5553 amelia.zodiacusque@@gmail.com F +@print{} Broderick 555-0542 broderick.aliquotiens@@yahoo.com R +@print{} Julie 555-6699 julie.perscrutabor@@skeeve.com F +@print{} Samuel 555-3430 samuel.lanceolis@@shu.edu A @end example @cindex actions, default @@ -2672,7 +2761,7 @@ action is to print all lines that match the pattern. @cindex actions, empty Thus, we could leave out the action (the @code{print} statement and the curly braces) in the previous example and the result would be the same: -@command{awk} prints all lines matching the pattern @samp{foo}. By comparison, +@command{awk} prints all lines matching the pattern @samp{li}. By comparison, omitting the @code{print} statement but retaining the curly braces makes an empty action that does nothing (i.e., no lines are printed). @@ -2817,29 +2906,23 @@ This program prints every line that contains the string strings, it is printed twice, once by each rule. This is what happens if we run this program on our two sample data files, -@file{BBS-list} and @file{inventory-shipped}: +@file{mail-list} and @file{inventory-shipped}: @example $ @kbd{awk '/12/ @{ print $0 @}} -> @kbd{/21/ @{ print $0 @}' BBS-list inventory-shipped} -@print{} aardvark 555-5553 1200/300 B -@print{} alpo-net 555-3412 2400/1200/300 A -@print{} barfly 555-7685 1200/300 A -@print{} bites 555-1675 2400/1200/300 A -@print{} core 555-2912 1200/300 C -@print{} fooey 555-1234 2400/1200/300 B -@print{} foot 555-6699 1200/300 B -@print{} macfoo 555-6480 1200/300 A -@print{} sdace 555-3430 2400/1200/300 A -@print{} sabafoo 555-2127 1200/300 C -@print{} sabafoo 555-2127 1200/300 C +> @kbd{/21/ @{ print $0 @}' mail-list inventory-shipped} +@print{} Anthony 555-3412 anthony.asserturo@@hotmail.com A +@print{} Camilla 555-2912 camilla.infusarum@@skynet.be R +@print{} Fabius 555-1234 fabius.undevicesimus@@ucb.edu F +@print{} Jean-Paul 555-2127 jeanpaul.campanorum@@nyu.edu R +@print{} Jean-Paul 555-2127 jeanpaul.campanorum@@nyu.edu R @print{} Jan 21 36 64 620 @print{} Apr 21 70 74 514 @end example @noindent -Note how the line beginning with @samp{sabafoo} -in @file{BBS-list} was printed twice, once for each rule. +Note how the line beginning with @samp{Jean-Paul} +in @file{mail-list} was printed twice, once for each rule. @node More Complex @section A More Complex Example @@ -2918,7 +3001,7 @@ separate rule, like this: @example awk '/12/ @{ print $0 @} - /21/ @{ print $0 @}' BBS-list inventory-shipped + /21/ @{ print $0 @}' mail-list inventory-shipped @end example @cindex @command{gawk}, newlines in @@ -3033,8 +3116,8 @@ noticed because it is ``hidden'' inside the comment. Thus, the @code{BEGIN} is noted as a syntax error. @cindex statements, multiple -@cindex @code{;} (semicolon) -@cindex semicolon (@code{;}) +@cindex @code{;} (semicolon), separating statements in actions +@cindex semicolon (@code{;}), separating statements in actions When @command{awk} statements within one rule are short, you might want to put more than one of them on a line. This is accomplished by separating the statements with a semicolon (@samp{;}). @@ -3094,6 +3177,7 @@ used once, and thrown away. Because @command{awk} programs are interpreted, you can avoid the (usually lengthy) compilation part of the typical edit-compile-test-debug cycle of software development. +@cindex Brian Kernighan's @command{awk} Complex programs have been written in @command{awk}, including a complete retargetable assembler for eight-bit microprocessors (@pxref{Glossary}, for more information), and a microcode assembler for a special-purpose Prolog @@ -3156,10 +3240,19 @@ There are two ways to run @command{awk}---with an explicit program or with one or more program files. Here are templates for both of them; items enclosed in [@dots{}] in these templates are optional: +@ifnotdocbook @example awk @r{[@var{options}]} -f progfile @r{[@code{--}]} @var{file} @dots{} awk @r{[@var{options}]} @r{[@code{--}]} '@var{program}' @var{file} @dots{} @end example +@end ifnotdocbook + +@c FIXME - find a better way to mark this up in docbook +@docbook +<screen>awk [<replaceable>options</replaceable>] -f progfile [<literal>--</literal>] <replaceable>file</replaceable> … +awk [<replaceable>options</replaceable>] [<literal>--</literal>] '<replaceable>program</replaceable>' <replaceable>file</replaceable> … +</screen> +@end docbook @cindex GNU long options @cindex long options @@ -3325,6 +3418,7 @@ Print the short version of the General Public License and then exit. @itemx --dump-variables@r{[}=@var{file}@r{]} @cindex @option{-d} option @cindex @option{--dump-variables} option +@cindex dump all variables of a program @cindex @file{awkvars.out} file @cindex files, @file{awkvars.out} @cindex variables, global, printing list of @@ -3478,7 +3572,7 @@ care to search for all occurrences of each inappropriate construct. As @cindex @option{--bignum} option Force arbitrary precision arithmetic on numbers. This option has no effect if @command{gawk} is not compiled to use the GNU MPFR and MP libraries -(@pxref{Arbitrary Precision Arithmetic}). +(@pxref{Gawk and MPFR}). @item -n @itemx --non-decimal-data @@ -3731,6 +3825,7 @@ file at all. @cindex @command{gawk}, @code{ARGIND} variable in @cindex @code{ARGIND} variable, command-line arguments +@cindex @code{ARGV} array, indexing into @cindex @code{ARGC}/@code{ARGV} variables, command-line arguments All these arguments are made available to your @command{awk} program in the @code{ARGV} array (@pxref{Built-in Variables}). Command-line options @@ -3741,6 +3836,7 @@ sets the variable @code{ARGIND} to the index in @code{ARGV} of the current element. @cindex input files, variable assignments and +@cindex variable assignments and input files The distinction between file name arguments and variable-assignment arguments is made when @command{awk} is about to open the next input file. At that point in execution, it checks the file name to see whether @@ -3818,6 +3914,7 @@ this file name itself.) @node Environment Variables @section The Environment Variables @command{gawk} Uses +@cindex environment variables used by @command{gawk} A number of environment variables influence how @command{gawk} behaves. @@ -3833,8 +3930,7 @@ behaves. @node AWKPATH Variable @subsection The @env{AWKPATH} Environment Variable @cindex @env{AWKPATH} environment variable -@cindex directories, searching -@cindex search paths +@cindex directories, searching for source files @cindex search paths, for source files @cindex differences in @command{awk} and @command{gawk}, @code{AWKPATH} environment variable @ifinfo @@ -3846,12 +3942,12 @@ implementations, you must supply a precise path name for each program file, unless the file is in the current directory. But in @command{gawk}, if the file name supplied to the @option{-f} or @option{-i} options -does not contain a @samp{/}, then @command{gawk} searches a list of +does not contain a directory separator @samp{/}, then @command{gawk} searches a list of directories (called the @dfn{search path}), one by one, looking for a file with the specified name. The search path is a string consisting of directory names -separated by colons. @command{gawk} gets its search path from the +separated by colons@footnote{Semicolons on MS-Windows and MS-DOS.}. @command{gawk} gets its search path from the @env{AWKPATH} environment variable. If that variable does not exist, @command{gawk} uses a default path, @samp{.:/usr/local/share/awk}.@footnote{Your version of @command{gawk} @@ -3909,8 +4005,7 @@ found, and @command{gawk} no longer needs to use @env{AWKPATH}. @node AWKLIBPATH Variable @subsection The @env{AWKLIBPATH} Environment Variable @cindex @env{AWKLIBPATH} environment variable -@cindex directories, searching -@cindex search paths +@cindex directories, searching for shared libraries @cindex search paths, for shared libraries @cindex differences in @command{awk} and @command{gawk}, @code{AWKLIBPATH} environment variable @@ -4195,7 +4290,6 @@ they will @emph{not} be in the next release). @c update this section for each release! -@cindex @code{PROCINFO} array The process-related special files @file{/dev/pid}, @file{/dev/ppid}, @file{/dev/pgrpid}, and @file{/dev/user} were deprecated in @command{gawk} 3.1, but still worked. As of version 4.0, they are no longer @@ -4221,6 +4315,7 @@ in case some option becomes obsolete in a future version of @command{gawk}. @author Obi-Wan @end quotation +@cindex shells, sea This @value{SECTION} intentionally left blank. @@ -4233,7 +4328,7 @@ blank. @table @code @item -W nostalgia @itemx --nostalgia -Print the message @code{"awk: bailing out near line 1"} and dump core. +Print the message @samp{awk: bailing out near line 1} and dump core. This option was inspired by the common behavior of very early versions of Unix @command{awk} and by a t--shirt. The message is @emph{not} subject to translation in non-English locales. @@ -4279,7 +4374,7 @@ long-undocumented ``feature'' of Unix @code{awk}. @node Regexp @chapter Regular Expressions -@cindex regexp, See regular expressions +@cindex regexp @c STARTOFRANGE regexp @cindex regular expressions @@ -4288,8 +4383,8 @@ set of strings. Because regular expressions are such a fundamental part of @command{awk} programming, their format and use deserve a separate @value{CHAPTER}. -@cindex forward slash (@code{/}) -@cindex @code{/} (forward slash) +@cindex forward slash (@code{/}) to enclose regular expressions +@cindex @code{/} (forward slash) to enclose regular expressions A regular expression enclosed in slashes (@samp{/}) is an @command{awk} pattern that matches every input record whose text belongs to that set. @@ -4326,14 +4421,14 @@ slashes. Then the regular expression is tested against the entire text of each record. (Normally, it only needs to match some part of the text in order to succeed.) For example, the following prints the second field of each record that contains the string -@samp{foo} anywhere in it: +@samp{li} anywhere in it: @example -$ @kbd{awk '/foo/ @{ print $2 @}' BBS-list} -@print{} 555-1234 +$ @kbd{awk '/li/ @{ print $2 @}' mail-list} +@print{} 555-5553 +@print{} 555-0542 @print{} 555-6699 -@print{} 555-6480 -@print{} 555-2127 +@print{} 555-3430 @end example @cindex regular expressions, operators @@ -4345,9 +4440,9 @@ $ @kbd{awk '/foo/ @{ print $2 @}' BBS-list} @cindex @code{!} (exclamation point), @code{!~} operator @cindex exclamation point (@code{!}), @code{!~} operator @c @cindex operators, @code{!~} -@cindex @code{if} statement -@cindex @code{while} statement -@cindex @code{do}-@code{while} statement +@cindex @code{if} statement, use of regexps in +@cindex @code{while} statement, use of regexps in +@cindex @code{do}-@code{while} statement, use of regexps in @c @cindex statements, @code{if} @c @cindex statements, @code{while} @c @cindex statements, @code{do} @@ -4406,6 +4501,7 @@ $ @kbd{awk '$1 !~ /J/' inventory-shipped} @end example @cindex regexp constants +@cindex constant regexps @cindex regular expressions, constants, See regexp constants When a regexp is enclosed in slashes, such as @code{/foo/}, we call it a @dfn{regexp constant}, much like @code{5.27} is a numeric constant and @@ -4414,7 +4510,7 @@ a @dfn{regexp constant}, much like @code{5.27} is a numeric constant and @node Escape Sequences @section Escape Sequences -@cindex escape sequences +@cindex escape sequences, in strings @cindex backslash (@code{\}), in escape sequences @cindex @code{\} (backslash), in escape sequences Some characters cannot be included literally in string constants @@ -4584,6 +4680,7 @@ leaves what happens as undefined. There are two choices: @c @cindex automatic warnings @c @cindex warnings, automatic +@cindex Brian Kernighan's @command{awk} @table @asis @item Strip the backslash out This is what Brian Kernighan's @command{awk} and @command{gawk} both do. @@ -4597,6 +4694,7 @@ two backslashes in the string: @samp{FS = @w{"[ \t]+\\|[ \t]+"}}.) @cindex @command{gawk}, escape sequences @cindex Unix @command{awk}, backslashes in escape sequences +@cindex @command{mawk} utility @item Leave the backslash alone Some other @command{awk} implementations do this. In such implementations, typing @code{"a\qc"} is the same as typing @@ -4625,6 +4723,7 @@ leaves what happens as undefined. There are two choices: @c @cindex automatic warnings @c @cindex warnings, automatic +@cindex Brian Kernighan's @command{awk} @table @asis @item Strip the backslash out This is what Brian Kernighan's @command{awk} and @command{gawk} both do. @@ -4638,6 +4737,7 @@ two backslashes in the string: @samp{FS = @w{"[ \t]+\\|[ \t]+"}}.) @cindex @command{gawk}, escape sequences @cindex Unix @command{awk}, backslashes in escape sequences +@cindex @command{mawk} utility @item Leave the backslash alone Some other @command{awk} implementations do this. In such implementations, typing @code{"a\qc"} is the same as typing @@ -4704,6 +4804,7 @@ escape sequences literally when used in regexp constants. Thus, @section Regular Expression Operators @c STARTOFRANGE regexpo @cindex regular expressions, operators +@cindex metacharacters in regular expressions You can combine regular expressions with special characters, called @dfn{regular expression operators} or @dfn{metacharacters}, to @@ -4722,8 +4823,8 @@ Here is a list of metacharacters. All characters that are not escape sequences and that are not listed in the table stand for themselves: @table @code -@cindex backslash (@code{\}) -@cindex @code{\} (backslash) +@cindex backslash (@code{\}), regexp operator +@cindex @code{\} (backslash), regexp operator @item \ This is used to suppress the special meaning of a character when matching. For example, @samp{\$} @@ -4748,8 +4849,8 @@ The condition is not true in the following example: if ("line1\nLINE 2" ~ /^L/) @dots{} @end example -@cindex @code{$} (dollar sign) -@cindex dollar sign (@code{$}) +@cindex @code{$} (dollar sign), regexp operator +@cindex dollar sign (@code{$}), regexp operator @item $ This is similar to @samp{^}, but it matches only at the end of a string. For example, @samp{p$} @@ -4761,8 +4862,8 @@ The condition in the following example is not true: if ("line1\nLINE 2" ~ /1$/) @dots{} @end example -@cindex @code{.} (period) -@cindex period (@code{.}) +@cindex @code{.} (period), regexp operator +@cindex period (@code{.}), regexp operator @item . @r{(period)} This matches any single character, @emph{including} the newline character. For example, @samp{.P} @@ -4778,11 +4879,12 @@ character, which is a character with all bits equal to zero. Otherwise, @sc{nul} is just another character. Other versions of @command{awk} may not be able to match the @sc{nul} character. -@cindex @code{[]} (square brackets) -@cindex square brackets (@code{[]}) +@cindex @code{[]} (square brackets), regexp operator +@cindex square brackets (@code{[]}), regexp operator @cindex bracket expressions @cindex character sets, See Also bracket expressions @cindex character lists, See bracket expressions +@cindex character classes, See bracket expressions @item [@dots{}] This is called a @dfn{bracket expression}.@footnote{In other literature, you may see a bracket expression referred to as either a @@ -4815,8 +4917,8 @@ means it matches any string that starts with @samp{P} or contains a digit. The alternation applies to the largest possible regexps on either side. -@cindex @code{()} (parentheses) -@cindex parentheses @code{()} +@cindex @code{()} (parentheses), regexp operator +@cindex parentheses @code{()}, regexp operator @item (@dots{}) Parentheses are used for grouping in regular expressions, as in arithmetic. They can be used to concatenate regular expressions @@ -4844,8 +4946,8 @@ prints every record in @file{sample} containing a string of the form Notice the escaping of the parentheses by preceding them with backslashes. -@cindex @code{+} (plus sign) -@cindex plus sign (@code{+}) +@cindex @code{+} (plus sign), regexp operator +@cindex plus sign (@code{+}), regexp operator @item + This symbol is similar to @samp{*}, except that the preceding expression must be matched at least once. This means that @samp{wh+y} @@ -4858,14 +4960,14 @@ way of writing the last @samp{*} example: awk '/\(c[ad]+r x\)/ @{ print @}' sample @end example -@cindex @code{?} (question mark) regexp operator -@cindex question mark (@code{?}) regexp operator +@cindex @code{?} (question mark), regexp operator +@cindex question mark (@code{?}), regexp operator @item ? This symbol is similar to @samp{*}, except that the preceding expression can be matched either once or not at all. For example, @samp{fe?d} matches @samp{fed} and @samp{fd}, but nothing else. -@cindex interval expressions +@cindex interval expressions, regexp operator @item @{@var{n}@} @itemx @{@var{n},@} @itemx @{@var{n},@var{m}@} @@ -4942,6 +5044,7 @@ expressions are not available in regular expressions. @cindex bracket expressions @cindex bracket expressions, range expressions @cindex range expressions (regexps) +@cindex character lists in regular expression As mentioned earlier, a bracket expression matches any character amongst those listed between the opening and closing square brackets. @@ -5181,10 +5284,10 @@ Matches the empty string at the end of a buffer (string). @end table -@cindex @code{^} (caret) -@cindex caret (@code{^}) -@cindex @code{?} (question mark) regexp operator -@cindex question mark (@code{?}) regexp operator +@cindex @code{^} (caret), regexp operator +@cindex caret (@code{^}), regexp operator +@cindex @code{?} (question mark), regexp operator +@cindex question mark (@code{?}), regexp operator Because @samp{^} and @samp{$} always work in terms of the beginning and end of strings, these operators don't add any new capabilities for @command{awk}. They are provided for compatibility with other @@ -5205,7 +5308,7 @@ lesser of two evils. @c @c Should really do this with file inclusion. @cindex regular expressions, @command{gawk}, command-line options -@cindex @command{gawk}, command-line options +@cindex @command{gawk}, command-line options, and regular expressions The various command-line options (@pxref{Options}) control how @command{gawk} interprets characters in regexps: @@ -5228,6 +5331,7 @@ Only POSIX regexps are supported; the GNU operators are not special (e.g., @samp{\w} matches a literal @samp{w}). Interval expressions are allowed. +@cindex Brian Kernighan's @command{awk} @item @code{--traditional} Traditional Unix @command{awk} regexps are matched. The GNU operators are not special, and interval expressions are not available. @@ -5283,7 +5387,7 @@ This works in any POSIX-compliant @command{awk}. @cindex tilde (@code{~}), @code{~} operator @cindex @code{!} (exclamation point), @code{!~} operator @cindex exclamation point (@code{!}), @code{!~} operator -@cindex @code{IGNORECASE} variable +@cindex @code{IGNORECASE} variable, with @code{~} and @code{!~} operators @cindex @command{gawk}, @code{IGNORECASE} variable in @c @cindex variables, @code{IGNORECASE} Another method, specific to @command{gawk}, is to set the variable @@ -5548,6 +5652,7 @@ occur often in practice, but it's worth noting for future reference. @chapter Reading Input Files @c STARTOFRANGE infir +@cindex reading input files @cindex input files, reading @cindex input files @cindex @code{FILENAME} variable @@ -5634,68 +5739,79 @@ To do this, use the special @code{BEGIN} pattern (@pxref{BEGIN/END}). For example: -@cindex @code{BEGIN} pattern @example -awk 'BEGIN @{ RS = "/" @} - @{ print $0 @}' BBS-list +awk 'BEGIN @{ RS = "u" @} + @{ print $0 @}' mail-list @end example @noindent -changes the value of @code{RS} to @code{"/"}, before reading any input. -This is a string whose first character is a slash; as a result, records -are separated by slashes. Then the input file is read, and the second +changes the value of @code{RS} to @samp{u}, before reading any input. +This is a string whose first character is the letter ``u;'' as a result, records +are separated by the letter ``u.'' Then the input file is read, and the second rule in the @command{awk} program (the action with no pattern) prints each record. Because each @code{print} statement adds a newline at the end of its output, this @command{awk} program copies the input -with each slash changed to a newline. Here are the results of running -the program on @file{BBS-list}: - -@example -$ @kbd{awk 'BEGIN @{ RS = "/" @}} -> @kbd{@{ print $0 @}' BBS-list} -@print{} aardvark 555-5553 1200 -@print{} 300 B -@print{} alpo-net 555-3412 2400 -@print{} 1200 -@print{} 300 A -@print{} barfly 555-7685 1200 -@print{} 300 A -@print{} bites 555-1675 2400 -@print{} 1200 -@print{} 300 A -@print{} camelot 555-0542 300 C -@print{} core 555-2912 1200 -@print{} 300 C -@print{} fooey 555-1234 2400 -@print{} 1200 -@print{} 300 B -@print{} foot 555-6699 1200 -@print{} 300 B -@print{} macfoo 555-6480 1200 -@print{} 300 A -@print{} sdace 555-3430 2400 -@print{} 1200 -@print{} 300 A -@print{} sabafoo 555-2127 1200 -@print{} 300 C -@print{} +with each @samp{u} changed to a newline. Here are the results of running +the program on @file{mail-list}: + +@example +$ @kbd{awk 'BEGIN @{ RS = "u" @}} +> @kbd{@{ print $0 @}' mail-list} +@print{} Amelia 555-5553 amelia.zodiac +@print{} sq +@print{} e@@gmail.com F +@print{} Anthony 555-3412 anthony.assert +@print{} ro@@hotmail.com A +@print{} Becky 555-7685 becky.algebrar +@print{} m@@gmail.com A +@print{} Bill 555-1675 bill.drowning@@hotmail.com A +@print{} Broderick 555-0542 broderick.aliq +@print{} otiens@@yahoo.com R +@print{} Camilla 555-2912 camilla.inf +@print{} sar +@print{} m@@skynet.be R +@print{} Fabi +@print{} s 555-1234 fabi +@print{} s. +@print{} ndevicesim +@print{} s@@ +@print{} cb.ed +@print{} F +@print{} J +@print{} lie 555-6699 j +@print{} lie.perscr +@print{} tabor@@skeeve.com F +@print{} Martin 555-6480 martin.codicib +@print{} s@@hotmail.com A +@print{} Sam +@print{} el 555-3430 sam +@print{} el.lanceolis@@sh +@print{} .ed +@print{} A +@print{} Jean-Pa +@print{} l 555-2127 jeanpa +@print{} l.campanor +@print{} m@@ny +@print{} .ed +@print{} R +@print{} @end example @noindent -Note that the entry for the @samp{camelot} BBS is not split. +Note that the entry for the name @samp{Bill} is not split. In the original data file (@pxref{Sample Data Files}), the line looks like this: @example -camelot 555-0542 300 C +Bill 555-1675 bill.drowning@@hotmail.com A @end example @noindent -It has one baud rate only, so there are no slashes in the record, -unlike the others which have two or more baud rates. -In fact, this record is treated as part of the record -for the @samp{core} BBS; the newline separating them in the output +It contains no @samp{u} so there is no reason to split the record, +unlike the others which have one or more occurrences of the @samp{u}. +In fact, this record is treated as part of the previous record; +the newline separating them in the output is the original newline in the data file, not the one added by @command{awk} when it printed the record! @@ -5706,14 +5822,17 @@ using the variable-assignment feature (@pxref{Other Arguments}): @example -awk '@{ print $0 @}' RS="/" BBS-list +awk '@{ print $0 @}' RS="u" mail-list @end example @noindent -This sets @code{RS} to @samp{/} before processing @file{BBS-list}. +This sets @code{RS} to @samp{u} before processing @file{mail-list}. -Using an unusual character such as @samp{/} for the record separator -produces correct behavior in the vast majority of cases. +Using an alphabetic character such as @samp{u} for the record separator +is highly likely to produce strange results. +Using an unusual character such as @samp{/} is more likely to +produce correct behavior in the majority of cases, but there +are no guarantees. The moral is: Know Your Data. There is one unusual case, that occurs when @command{gawk} is being fully POSIX-compliant (@pxref{Options}). @@ -5735,6 +5854,7 @@ Reaching the end of an input file terminates the current input record, even if the last character in the file is not the character in @code{RS}. @value{DARKCORNER} +@cindex empty strings @cindex null strings @cindex strings, empty, See null strings The empty string @code{""} (a string without any characters) @@ -5871,7 +5991,7 @@ character as a record separator. However, this is a special case: @command{mawk} does not allow embedded @sc{nul} characters in strings. @cindex records, treating files as -@cindex files, as single records +@cindex treating files, as single records The best way to treat a whole file as a single record is to simply read the file in, one record at a time, concatenating each record onto the end of the previous ones. @@ -5922,7 +6042,7 @@ character as a record separator. However, this is a special case: @command{mawk} does not allow embedded @sc{nul} characters in strings. @cindex records, treating files as -@cindex files, as single records +@cindex treating files, as single records The best way to treat a whole file as a single record is to simply read the file in, one record at a time, concatenating each record onto the end of the previous ones. @@ -6000,31 +6120,29 @@ when you are not interested in specific fields. Here are some more examples: @example -$ @kbd{awk '$1 ~ /foo/ @{ print $0 @}' BBS-list} -@print{} fooey 555-1234 2400/1200/300 B -@print{} foot 555-6699 1200/300 B -@print{} macfoo 555-6480 1200/300 A -@print{} sabafoo 555-2127 1200/300 C +$ @kbd{awk '$1 ~ /li/ @{ print $0 @}' mail-list} +@print{} Amelia 555-5553 amelia.zodiacusque@@gmail.com F +@print{} Julie 555-6699 julie.perscrutabor@@skeeve.com F @end example @noindent -This example prints each record in the file @file{BBS-list} whose first -field contains the string @samp{foo}. The operator @samp{~} is called a +This example prints each record in the file @file{mail-list} whose first +field contains the string @samp{li}. The operator @samp{~} is called a @dfn{matching operator} (@pxref{Regexp Usage}); it tests whether a string (here, the field @code{$1}) matches a given regular expression. By contrast, the following example -looks for @samp{foo} in @emph{the entire record} and prints the first +looks for @samp{li} in @emph{the entire record} and prints the first field and the last field for each matching input record: @example -$ @kbd{awk '/foo/ @{ print $1, $NF @}' BBS-list} -@print{} fooey B -@print{} foot B -@print{} macfoo A -@print{} sabafoo C +$ @kbd{awk '/li/ @{ print $1, $NF @}' mail-list} +@print{} Amelia F +@print{} Broderick R +@print{} Julie F +@print{} Samuel A @end example @c ENDOFRANGE fiex @@ -6052,7 +6170,7 @@ the record has fewer than 20 fields, so this prints a blank line. Here is another example of using expressions as field numbers: @example -awk '@{ print $(2*2) @}' BBS-list +awk '@{ print $(2*2) @}' mail-list @end example @command{awk} evaluates the expression @samp{(2*2)} and uses @@ -6061,8 +6179,8 @@ represents multiplication, so the expression @samp{2*2} evaluates to four. The parentheses are used so that the multiplication is done before the @samp{$} operation; they are necessary whenever there is a binary operator in the field-number expression. This example, then, prints the -hours of operation (the fourth field) for every line of the file -@file{BBS-list}. (All of the @command{awk} operators are listed, in +type of relationship (the fourth field) for every line of the file +@file{mail-list}. (All of the @command{awk} operators are listed, in order of decreasing precedence, in @ref{Precedence}.) @@ -6504,7 +6622,7 @@ was ignored when finding @code{$1}, it is not part of the new @code{$0}. Finally, the last @code{print} statement prints the new @code{$0}. @cindex @code{FS}, containing @code{^} -@cindex @code{^}, in @code{FS} +@cindex @code{^} (caret), in @code{FS} @cindex dark corner, @code{^}, in @code{FS} There is an additional subtlety to be aware of when using regular expressions for field splitting. @@ -6515,6 +6633,7 @@ different @command{awk} versions answer this question differently, and you should not rely on any specific behavior in your programs. @value{DARKCORNER} +@cindex Brian Kernighan's @command{awk} As a point of information, Brian Kernighan's @command{awk} allows @samp{^} to match only at the beginning of the record. @command{gawk} also works this way. For example: @@ -6558,7 +6677,7 @@ $ @kbd{echo a b | gawk 'BEGIN @{ FS = "" @}} @end example @cindex dark corner, @code{FS} as null string -@cindex FS variable, as null string +@cindex @code{FS} variable, as null string Traditionally, the behavior of @code{FS} equal to @code{""} was not defined. In this case, most versions of Unix @command{awk} simply treat the entire record as only having one field. @@ -6570,10 +6689,8 @@ behaves this way. @node Command Line Field Separator @subsection Setting @code{FS} from the Command Line -@cindex @option{-F} option -@cindex options, command-line -@cindex command line, options -@cindex field separators, on command line +@cindex @option{-F} option, command line +@cindex field separator, on command line @cindex command line, @code{FS} on@comma{} setting @cindex @code{FS} variable, setting from command line @@ -6623,66 +6740,59 @@ figures that you really want your fields to be separated with TABs and not @samp{t}s. Use @samp{-v FS="t"} or @samp{-F"[t]"} on the command line if you really do want to separate your fields with @samp{t}s. -As an example, let's use an @command{awk} program file called @file{baud.awk} -that contains the pattern @code{/300/} and the action @samp{print $1}: +As an example, let's use an @command{awk} program file called @file{edu.awk} +that contains the pattern @code{/edu/} and the action @samp{print $1}: @example -/300/ @{ print $1 @} +/edu/ @{ print $1 @} @end example Let's also set @code{FS} to be the @samp{-} character and run the -program on the file @file{BBS-list}. The following command prints a -list of the names of the bulletin boards that operate at 300 baud and +program on the file @file{mail-list}. The following command prints a +list of the names of the people that work at or attend a university, and the first three digits of their phone numbers: @c tweaked to make the tex output look better in @smallbook @example -$ @kbd{awk -F- -f baud.awk BBS-list} -@print{} aardvark 555 -@print{} alpo -@print{} barfly 555 -@print{} bites 555 -@print{} camelot 555 -@print{} core 555 -@print{} fooey 555 -@print{} foot 555 -@print{} macfoo 555 -@print{} sdace 555 -@print{} sabafoo 555 +$ @kbd{awk -F- -f edu.awk mail-list} +@print{} Fabius 555 +@print{} Samuel 555 +@print{} Jean @end example @noindent -Note the second line of output. The second line +Note the third line of output. The third line in the original file looked like this: @example -alpo-net 555-3412 2400/1200/300 A +Jean-Paul 555-2127 jeanpaul.campanorum@@nyu.edu R @end example -The @samp{-} as part of the system's name was used as the field +The @samp{-} as part of the person's name was used as the field separator, instead of the @samp{-} in the phone number that was originally intended. This demonstrates why you have to be careful in choosing your field and record separators. @cindex Unix @command{awk}, password files@comma{} field separators and -Perhaps the most common use of a single character as the field -separator occurs when processing the Unix system password file. -On many Unix systems, each user has a separate entry in the system password -file, one line per user. The information in these lines is separated -by colons. The first field is the user's login name and the second is -the user's (encrypted or shadow) password. A password file entry might look -like this: +Perhaps the most common use of a single character as the field separator +occurs when processing the Unix system password file. On many Unix +systems, each user has a separate entry in the system password file, one +line per user. The information in these lines is separated by colons. +The first field is the user's login name and the second is the user's +encrypted or shadow password. (A shadow password is indicated by the +presence of a single @samp{x} in the second field.) A password file +entry might look like this: @cindex Robbins, Arnold @example -arnold:xyzzy:2076:10:Arnold Robbins:/home/arnold:/bin/bash +arnold:x:2076:10:Arnold Robbins:/home/arnold:/bin/bash @end example The following program searches the system password file and prints -the entries for users who have no password: +the entries for users whose full name is not indicated: @example -awk -F: '$2 == ""' /etc/passwd +awk -F: '$5 == ""' /etc/passwd @end example @node Full Line Fields @@ -6745,7 +6855,7 @@ POSIX standard.) @cindex POSIX @command{awk}, field separators and -@cindex field separators, POSIX and +@cindex field separator, POSIX and According to the POSIX standard, @command{awk} is supposed to behave as if each record is split into fields at the time it is read. In particular, this means that if you change the value of @code{FS} @@ -6798,7 +6908,7 @@ root:nSijPlPhZZwgE:0:0:Root:/: @cindex POSIX @command{awk}, field separators and -@cindex field separators, POSIX and +@cindex field separator, POSIX and According to the POSIX standard, @command{awk} is supposed to behave as if each record is split into fields at the time it is read. In particular, this means that if you change the value of @code{FS} @@ -7158,6 +7268,7 @@ available for splitting regular strings (@pxref{String Functions}). @node Multiple Line @section Multiple-Line Records +@cindex multiple-line records @c STARTOFRANGE recm @cindex records, multiline @c STARTOFRANGE imr @@ -7209,7 +7320,8 @@ after the last record, the final newline is removed from the record. In the second case, this special processing is not done. @value{DARKCORNER} -@cindex field separators, in multiline records +@cindex field separator, in multiline records +@cindex @code{FS}, in multiline records Now that the input is separated into records, the second step is to separate the fields in the record. One way to do this is to divide each of the lines into fields in the normal manner. This happens by default @@ -7357,7 +7469,7 @@ and study the @code{getline} command @emph{after} you have reviewed the rest of this @value{DOCUMENT} and have a good knowledge of how @command{awk} works. @cindex @command{gawk}, @code{ERRNO} variable in -@cindex @code{ERRNO} variable +@cindex @code{ERRNO} variable, with @command{getline} command @cindex differences in @command{awk} and @command{gawk}, @code{getline} command @cindex @code{getline} command, return values @cindex @option{--sandbox} option, input redirection with @code{getline} @@ -7453,6 +7565,7 @@ rule in the program. @xref{Next Statement}. @node Getline/Variable @subsection Using @code{getline} into a Variable +@cindex @code{getline} into a variable @cindex variables, @code{getline} command into@comma{} using You can use @samp{getline @var{var}} to read the next record from @@ -7504,6 +7617,7 @@ the value of @code{NF} do not change. @node Getline/File @subsection Using @code{getline} from a File +@cindex @code{getline} from a file @cindex input redirection @cindex redirection of input @cindex @code{<} (left angle bracket), @code{<} operator (I/O) @@ -7552,8 +7666,6 @@ from the file @var{file}, and put it in the variable @var{var}. As above, @var{file} is a string-valued expression that specifies the file from which to read. -@cindex @command{gawk}, @code{RT} variable in -@cindex @code{RT} variable In this version of @code{getline}, none of the built-in variables are changed and the record is not split into fields. The only variable changed is @var{var}.@footnote{This is not quite true. @code{RT} could @@ -7578,7 +7690,6 @@ Note here how the name of the extra input file is not built into the program; it is taken directly from the data, specifically from the second field on the @samp{@@include} line. -@cindex @code{close()} function The @code{close()} function is called to ensure that if two identical @samp{@@include} lines appear in the input, the entire specified file is included twice. @@ -7595,6 +7706,7 @@ that does handle nested @samp{@@include} statements. @subsection Using @code{getline} from a Pipe @c From private email, dated October 2, 1988. Used by permission, March 2013. +@cindex Kernighan, Brian @quotation @i{Omniscience has much to recommend it. Failing that, attention to details would be useful.} @@ -7604,7 +7716,7 @@ Failing that, attention to details would be useful.} @cindex @code{|} (vertical bar), @code{|} operator (I/O) @cindex vertical bar (@code{|}), @code{|} operator (I/O) @cindex input pipeline -@cindex pipes, input +@cindex pipe, input @cindex operators, input/output The output of a command can also be piped into @code{getline}, using @samp{@var{command} | getline}. In @@ -7628,7 +7740,6 @@ produced by running the rest of the line as a shell command: @end example @noindent -@cindex @code{close()} function The @code{close()} function is called to ensure that if two identical @samp{@@execute} lines appear in the input, the command is run for each one. @@ -7682,6 +7793,8 @@ because the concatenation operator is not parenthesized. You should write it as @samp{(@w{"echo "} "date") | getline} if you want your program to be portable to all @command{awk} implementations. +@cindex Brian Kernighan's @command{awk} +@cindex @command{mawk} utility @quotation NOTE Unfortunately, @command{gawk} has not been consistent in its treatment of a construct like @samp{@w{"echo "} "date" | getline}. @@ -8006,6 +8119,7 @@ indefinitely until some other process opens it for writing. @node Command line directories @section Directories On The Command Line +@cindex differences in @command{awk} and @command{gawk}, command line directories @cindex directories, command line @cindex command line, directories on @@ -8249,13 +8363,29 @@ program by using a new value of @code{OFS}. @example $ @kbd{awk 'BEGIN @{ OFS = ";"; ORS = "\n\n" @}} -> @kbd{@{ print $1, $2 @}' BBS-list} -@print{} aardvark;555-5553 -@print{} -@print{} alpo-net;555-3412 -@print{} -@print{} barfly;555-7685 -@dots{} +> @kbd{@{ print $1, $2 @}' mail-list} +@print{} Amelia;555-5553 +@print{} +@print{} Anthony;555-3412 +@print{} +@print{} Becky;555-7685 +@print{} +@print{} Bill;555-1675 +@print{} +@print{} Broderick;555-0542 +@print{} +@print{} Camilla;555-2912 +@print{} +@print{} Fabius;555-1234 +@print{} +@print{} Julie;555-6699 +@print{} +@print{} Martin;555-6480 +@print{} +@print{} Samuel;555-3430 +@print{} +@print{} Jean-Paul;555-2127 +@print{} @end example If the value of @code{ORS} does not contain a newline, the program's output @@ -8277,7 +8407,7 @@ numbers can be formatted. The different format specifications are discussed more fully in @ref{Control Letters}. -@cindex @code{sprintf()} function +@cindexawkfunc{sprintf} @cindex @code{OFMT} variable @cindex output, format specifier@comma{} @code{OFMT} The built-in variable @code{OFMT} contains the default format specification @@ -8343,7 +8473,7 @@ parentheses are necessary if any of the item expressions use the @samp{>} relational operator; otherwise, it can be confused with an output redirection (@pxref{Redirection}). -@cindex format strings +@cindex format specifiers The difference between @code{printf} and @code{print} is the @var{format} argument. This is an expression whose value is taken as a string; it specifies how to output each of the other arguments. It is called the @@ -8729,30 +8859,30 @@ The following simple example shows how to use @code{printf} to make an aligned table: @example -awk '@{ printf "%-10s %s\n", $1, $2 @}' BBS-list +awk '@{ printf "%-10s %s\n", $1, $2 @}' mail-list @end example @noindent This command -prints the names of the bulletin boards (@code{$1}) in the file -@file{BBS-list} as a string of 10 characters that are left-justified. It also +prints the names of the people (@code{$1}) in the file +@file{mail-list} as a string of 10 characters that are left-justified. It also prints the phone numbers (@code{$2}) next on the line. This produces an aligned two-column table of names and phone numbers, as shown here: @example -$ @kbd{awk '@{ printf "%-10s %s\n", $1, $2 @}' BBS-list} -@print{} aardvark 555-5553 -@print{} alpo-net 555-3412 -@print{} barfly 555-7685 -@print{} bites 555-1675 -@print{} camelot 555-0542 -@print{} core 555-2912 -@print{} fooey 555-1234 -@print{} foot 555-6699 -@print{} macfoo 555-6480 -@print{} sdace 555-3430 -@print{} sabafoo 555-2127 +$ @kbd{awk '@{ printf "%-10s %s\n", $1, $2 @}' mail-list} +@print{} Amelia 555-5553 +@print{} Anthony 555-3412 +@print{} Becky 555-7685 +@print{} Bill 555-1675 +@print{} Broderick 555-0542 +@print{} Camilla 555-2912 +@print{} Fabius 555-1234 +@print{} Julie 555-6699 +@print{} Martin 555-6480 +@print{} Samuel 555-3430 +@print{} Jean-Paul 555-2127 @end example In this case, the phone numbers had to be printed as strings because @@ -8773,7 +8903,7 @@ the @command{awk} program: @example awk 'BEGIN @{ print "Name Number" print "---- ------" @} - @{ printf "%-10s %s\n", $1, $2 @}' BBS-list + @{ printf "%-10s %s\n", $1, $2 @}' mail-list @end example The above example mixes @code{print} and @code{printf} statements in @@ -8783,7 +8913,7 @@ same results: @example awk 'BEGIN @{ printf "%-10s %s\n", "Name", "Number" printf "%-10s %s\n", "----", "------" @} - @{ printf "%-10s %s\n", $1, $2 @}' BBS-list + @{ printf "%-10s %s\n", $1, $2 @}' mail-list @end example @noindent @@ -8798,7 +8928,7 @@ emphasized by storing it in a variable, like this: awk 'BEGIN @{ format = "%-10s %s\n" printf format, "Name", "Number" printf format, "----", "------" @} - @{ printf format, $1, $2 @}' BBS-list + @{ printf format, $1, $2 @}' mail-list @end example @c !!! exercise @@ -8855,20 +8985,20 @@ before the first output is written to it. Subsequent writes to the same @var{output-file} do not erase @var{output-file}, but append to it. (This is different from how you use redirections in shell scripts.) If @var{output-file} does not exist, it is created. For example, here -is how an @command{awk} program can write a list of BBS names to one +is how an @command{awk} program can write a list of peoples' names to one file named @file{name-list}, and a list of phone numbers to another file named @file{phone-list}: @example $ @kbd{awk '@{ print $2 > "phone-list"} -> @kbd{print $1 > "name-list" @}' BBS-list} +> @kbd{print $1 > "name-list" @}' mail-list} $ @kbd{cat phone-list} @print{} 555-5553 @print{} 555-3412 @dots{} $ @kbd{cat name-list} -@print{} aardvark -@print{} alpo-net +@print{} Amelia +@print{} Anthony @dots{} @end example @@ -8886,7 +9016,7 @@ appended to the file. If @var{output-file} does not exist, then it is created. @cindex @code{|} (vertical bar), @code{|} operator (I/O) -@cindex pipes, output +@cindex pipe, output @cindex output, pipes @item print @var{items} | @var{command} It is possible to send output to another program through a pipe @@ -8897,7 +9027,7 @@ to another process created to execute @var{command}. The redirection argument @var{command} is actually an @command{awk} expression. Its value is converted to a string whose contents give the shell command to be run. For example, the following produces two -files, one unsorted list of BBS names, and one list sorted in reverse +files, one unsorted list of peoples' names, and one list sorted in reverse alphabetical order: @ignore @@ -8910,7 +9040,7 @@ alone for now and let's hope no-one notices. @example awk '@{ print $1 > "names.unsorted" command = "sort -r > names.sorted" - print $1 | command @}' BBS-list + print $1 | command @}' mail-list @end example The unsorted list is written with an ordinary redirection, while @@ -9158,9 +9288,9 @@ has been ported to, not just those that are POSIX-compliant: @cindex extensions, common@comma{} @code{/dev/stdout} special file @cindex extensions, common@comma{} @code{/dev/stderr} special file @cindex file names, standard streams in @command{gawk} -@cindex @code{/dev/@dots{}} special files (@command{gawk}) +@cindex @code{/dev/@dots{}} special files @cindex files, @code{/dev/@dots{}} special files -@cindex @code{/dev/fd/@var{N}} special files +@cindex @code{/dev/fd/@var{N}} special files (@command{gawk}) @table @file @item /dev/stdin The standard input (file descriptor 0). @@ -9261,7 +9391,7 @@ Doing so results in unpredictable behavior. @c STARTOFRANGE ofc @cindex output, files@comma{} closing @c STARTOFRANGE pc -@cindex pipes, closing +@cindex pipe, closing @c STARTOFRANGE cc @cindex coprocesses, closing @cindex @code{getline} command, coprocesses@comma{} using from @@ -9279,7 +9409,7 @@ the file name or command associated with it, and subsequent writes to the same file or command are appended to the previous writes. The file or pipe stays open until @command{awk} exits. -@cindex @code{close()} function +@cindexawkfunc{close} This implies that special steps are necessary in order to read the same file again from the beginning, or to rerun a shell command (rather than reading more output from the same command). The @code{close()} function @@ -9364,6 +9494,7 @@ a separate message. @cindex differences in @command{awk} and @command{gawk}, @code{close()} function @cindex portability, @code{close()} function and +@cindex @code{close()} function, portability If you use more files than the system allows you to have open, @command{gawk} attempts to multiplex the available open files among your data files. @command{gawk}'s ability to do this depends upon the @@ -9448,7 +9579,7 @@ retval = close(command) # syntax error in many Unix awks @end example @cindex @command{gawk}, @code{ERRNO} variable in -@cindex @code{ERRNO} variable +@cindex @code{ERRNO} variable, with @command{close()} function @command{gawk} treats @code{close()} as a function. The return value is @minus{}1 if the argument names something that was never opened with a redirection, or if there is @@ -9504,7 +9635,7 @@ retval = close(command) # syntax error in many Unix awks @end example @cindex @command{gawk}, @code{ERRNO} variable in -@cindex @code{ERRNO} variable +@cindex @code{ERRNO} variable, with @command{close()} function @command{gawk} treats @code{close()} as a function. The return value is @minus{}1 if the argument names something that was never opened with a redirection, or if there is @@ -9604,7 +9735,8 @@ have different forms, but are stored identically internally. @node Scalar Constants @subsubsection Numeric and String Constants -@cindex numeric, constants +@cindex constants, numeric +@cindex numeric constants A @dfn{numeric constant} stands for a number. This number can be an integer, a decimal fraction, or a number in scientific (exponential) notation.@footnote{The internal representation of all numbers, @@ -9630,7 +9762,7 @@ double-quotation marks. For example: @noindent @cindex differences in @command{awk} and @command{gawk}, strings -@cindex strings, length of +@cindex strings, length limitations represents the string whose contents are @samp{parrot}. Strings in @command{gawk} can be of any length, and they can contain any of the possible eight-bit ASCII characters including ASCII @sc{nul} (character code zero). @@ -9846,9 +9978,9 @@ upon the contents of the current input record. @cindex differences in @command{awk} and @command{gawk}, regexp constants @cindex dark corner, regexp constants, as arguments to user-defined functions -@cindex @code{gensub()} function (@command{gawk}) -@cindex @code{sub()} function -@cindex @code{gsub()} function +@cindexgawkfunc{gensub} +@cindexawkfunc{sub} +@cindexawkfunc{gsub} Constant regular expressions are also used as the first argument for the @code{gensub()}, @code{sub()}, and @code{gsub()} functions, as the second argument of the @code{match()} function, @@ -9981,7 +10113,7 @@ its position among the input file arguments---after the processing of the preceding input file argument. For example: @example -awk '@{ print $n @}' n=4 inventory-shipped n=2 BBS-list +awk '@{ print $n @}' n=4 inventory-shipped n=2 mail-list @end example @noindent @@ -9990,10 +10122,10 @@ the first file is read, the command line sets the variable @code{n} equal to four. This causes the fourth field to be printed in lines from @file{inventory-shipped}. After the first file has finished, but before the second file is started, @code{n} is set to two, so that the -second field is printed in lines from @file{BBS-list}: +second field is printed in lines from @file{mail-list}: @example -$ @kbd{awk '@{ print $n @}' n=4 inventory-shipped n=2 BBS-list} +$ @kbd{awk '@{ print $n @}' n=4 inventory-shipped n=2 mail-list} @print{} 15 @print{} 24 @dots{} @@ -10316,9 +10448,9 @@ specific operator to represent it. Instead, concatenation is performed by writing expressions next to one another, with no operator. For example: @example -$ @kbd{awk '@{ print "Field number one: " $1 @}' BBS-list} -@print{} Field number one: aardvark -@print{} Field number one: alpo-net +$ @kbd{awk '@{ print "Field number one: " $1 @}' mail-list} +@print{} Field number one: Amelia +@print{} Field number one: Anthony @dots{} @end example @@ -10326,9 +10458,9 @@ Without the space in the string constant after the @samp{:}, the line runs together. For example: @example -$ @kbd{awk '@{ print "Field number one:" $1 @}' BBS-list} -@print{} Field number one:aardvark -@print{} Field number one:alpo-net +$ @kbd{awk '@{ print "Field number one:" $1 @}' mail-list} +@print{} Field number one:Amelia +@print{} Field number one:Anthony @dots{} @end example @@ -10345,6 +10477,8 @@ name = "name" print "something meaningful" > file name @end example +@cindex Brian Kernighan's @command{awk} +@cindex @command{mawk} utility @noindent This produces a syntax error with some versions of Unix @command{awk}.@footnote{It happens that Brian Kernighan's @@ -11401,10 +11535,10 @@ The Boolean operators are: @item @var{boolean1} && @var{boolean2} True if both @var{boolean1} and @var{boolean2} are true. For example, the following statement prints the current input record if it contains -both @samp{2400} and @samp{foo}: +both @samp{edu} and @samp{li}: @example -if ($0 ~ /2400/ && $0 ~ /foo/) print +if ($0 ~ /edu/ && $0 ~ /li/) print @end example @cindex side effects, Boolean operators @@ -11417,11 +11551,11 @@ no substring @samp{foo} in the record. @item @var{boolean1} || @var{boolean2} True if at least one of @var{boolean1} or @var{boolean2} is true. For example, the following statement prints all records in the input -that contain @emph{either} @samp{2400} or -@samp{foo} or both: +that contain @emph{either} @samp{edu} or +@samp{li} or both: @example -if ($0 ~ /2400/ || $0 ~ /foo/) print +if ($0 ~ /edu/ || $0 ~ /li/) print @end example The subexpression @var{boolean2} is evaluated only if @var{boolean1} @@ -12016,7 +12150,7 @@ slashes (@code{/@var{regexp}/}), or any expression whose string value is used as a dynamic regular expression (@pxref{Computed Regexps}). The following example prints the second field of each input record -whose first field is precisely @samp{foo}: +whose first field is precisely @samp{li}: @cindex @code{/} (forward slash), patterns and @cindex forward slash (@code{/}), patterns and @@ -12025,68 +12159,65 @@ whose first field is precisely @samp{foo}: @cindex @code{!} (exclamation point), @code{!~} operator @cindex exclamation point (@code{!}), @code{!~} operator @example -$ @kbd{awk '$1 == "foo" @{ print $2 @}' BBS-list} +$ @kbd{awk '$1 == "li" @{ print $2 @}' mail-list} @end example @noindent -(There is no output, because there is no BBS site with the exact name @samp{foo}.) +(There is no output, because there is no person with the exact name @samp{li}.) Contrast this with the following regular expression match, which -accepts any record with a first field that contains @samp{foo}: +accepts any record with a first field that contains @samp{li}: @example -$ @kbd{awk '$1 ~ /foo/ @{ print $2 @}' BBS-list} -@print{} 555-1234 +$ @kbd{awk '$1 ~ /foo/ @{ print $2 @}' mail-list} +@print{} 555-5553 @print{} 555-6699 -@print{} 555-6480 -@print{} 555-2127 @end example @cindex regexp constants, as patterns @cindex patterns, regexp constants as A regexp constant as a pattern is also a special case of an expression -pattern. The expression @code{/foo/} has the value one if @samp{foo} -appears in the current input record. Thus, as a pattern, @code{/foo/} -matches any record containing @samp{foo}. +pattern. The expression @code{/li/} has the value one if @samp{li} +appears in the current input record. Thus, as a pattern, @code{/li/} +matches any record containing @samp{li}. @cindex Boolean expressions, as patterns Boolean expressions are also commonly used as patterns. Whether the pattern matches an input record depends on whether its subexpressions match. For example, the following command prints all the records in -@file{BBS-list} that contain both @samp{2400} and @samp{foo}: +@file{mail-list} that contain both @samp{edu} and @samp{li}: @example -$ @kbd{awk '/2400/ && /foo/' BBS-list} -@print{} fooey 555-1234 2400/1200/300 B +$ @kbd{awk '/edu/ && /li/' mail-list} +@print{} Samuel 555-3430 samuel.lanceolis@@shu.edu A @end example The following command prints all records in -@file{BBS-list} that contain @emph{either} @samp{2400} or @samp{foo} +@file{mail-list} that contain @emph{either} @samp{edu} or @samp{li} (or both, of course): @example -$ @kbd{awk '/2400/ || /foo/' BBS-list} -@print{} alpo-net 555-3412 2400/1200/300 A -@print{} bites 555-1675 2400/1200/300 A -@print{} fooey 555-1234 2400/1200/300 B -@print{} foot 555-6699 1200/300 B -@print{} macfoo 555-6480 1200/300 A -@print{} sdace 555-3430 2400/1200/300 A -@print{} sabafoo 555-2127 1200/300 C +$ @kbd{awk '/edu/ || /li/' mail-list} +@print{} Amelia 555-5553 amelia.zodiacusque@@gmail.com F +@print{} Broderick 555-0542 broderick.aliquotiens@@yahoo.com R +@print{} Fabius 555-1234 fabius.undevicesimus@@ucb.edu F +@print{} Julie 555-6699 julie.perscrutabor@@skeeve.com F +@print{} Samuel 555-3430 samuel.lanceolis@@shu.edu A +@print{} Jean-Paul 555-2127 jeanpaul.campanorum@@nyu.edu R @end example The following command prints all records in -@file{BBS-list} that do @emph{not} contain the string @samp{foo}: +@file{mail-list} that do @emph{not} contain the string @samp{li}: @example -$ @kbd{awk '! /foo/' BBS-list} -@print{} aardvark 555-5553 1200/300 B -@print{} alpo-net 555-3412 2400/1200/300 A -@print{} barfly 555-7685 1200/300 A -@print{} bites 555-1675 2400/1200/300 A -@print{} camelot 555-0542 300 C -@print{} core 555-2912 1200/300 C -@print{} sdace 555-3430 2400/1200/300 A +$ @kbd{awk '! /li/' mail-list} +@print{} Anthony 555-3412 anthony.asserturo@@hotmail.com A +@print{} Becky 555-7685 becky.algebrarum@@gmail.com A +@print{} Bill 555-1675 bill.drowning@@hotmail.com A +@print{} Camilla 555-2912 camilla.infusarum@@skynet.be R +@print{} Fabius 555-1234 fabius.undevicesimus@@ucb.edu F +@print{} Martin 555-6480 martin.codicibus@@hotmail.com A +@print{} Jean-Paul 555-2127 jeanpaul.campanorum@@nyu.edu R @end example @cindex @code{BEGIN} pattern, Boolean patterns and @@ -12190,6 +12321,11 @@ $ @kbd{echo Yes | gawk '(/1/,/2/) || /Yes/'} @error{} gawk: cmd. line:1: ^ syntax error @end example +@cindex range patterns, line continuation and +As a minor point of interest, although it is poor style, +POSIX allows you to put a newline after the comma in +a range pattern. @value{DARKCORNER} + @node BEGIN/END @subsection The @code{BEGIN} and @code{END} Special Patterns @@ -12214,28 +12350,30 @@ programmers. @node Using BEGIN/END @subsubsection Startup and Cleanup Actions +@cindex @code{BEGIN} pattern +@cindex @code{END} pattern A @code{BEGIN} rule is executed once only, before the first input record is read. Likewise, an @code{END} rule is executed once only, after all the input is read. For example: @example $ @kbd{awk '} -> @kbd{BEGIN @{ print "Analysis of \"foo\"" @}} -> @kbd{/foo/ @{ ++n @}} -> @kbd{END @{ print "\"foo\" appears", n, "times." @}' BBS-list} -@print{} Analysis of "foo" -@print{} "foo" appears 4 times. +> @kbd{BEGIN @{ print "Analysis of \"li\"" @}} +> @kbd{/li/ @{ ++n @}} +> @kbd{END @{ print "\"li\" appears in", n, "records." @}' mail-list} +@print{} Analysis of "li" +@print{} "li" appears in 4 records. @end example @cindex @code{BEGIN} pattern, operators and @cindex @code{END} pattern, operators and -This program finds the number of records in the input file @file{BBS-list} -that contain the string @samp{foo}. The @code{BEGIN} rule prints a title +This program finds the number of records in the input file @file{mail-list} +that contain the string @samp{li}. The @code{BEGIN} rule prints a title for the report. There is no need to use the @code{BEGIN} rule to initialize the counter @code{n} to zero, since @command{awk} does this automatically (@pxref{Variables}). The second rule increments the variable @code{n} every time a -record containing the pattern @samp{foo} is read. The @code{END} rule +record containing the pattern @samp{li} is read. The @code{END} rule prints the value of @code{n} at the end of the run. The special patterns @code{BEGIN} and @code{END} cannot be used in ranges @@ -12288,6 +12426,7 @@ to give @code{$0} a real value is to execute a @code{getline} command without a variable (@pxref{Getline}). Another way is simply to assign a value to @code{$0}. +@cindex Brian Kernighan's @command{awk} @cindex differences in @command{awk} and @command{gawk}, @code{BEGIN}/@code{END} patterns @cindex POSIX @command{awk}, @code{BEGIN}/@code{END} patterns @cindex @code{print} statement, @code{BEGIN}/@code{END} patterns and @@ -12356,7 +12495,7 @@ you can bypass the fatal error and move on to the next file on the command line. @cindex @command{gawk}, @code{ERRNO} variable in -@cindex @code{ERRNO} variable +@cindex @code{ERRNO} variable, with @code{BEGINFILE} pattern @cindex @code{nextfile} statement, @code{BEGINFILE}/@code{ENDFILE} patterns and You do this by checking if the @code{ERRNO} variable is not the empty string; if so, then @command{gawk} was not able to open the file. In @@ -12398,7 +12537,7 @@ both @code{BEGINFILE} and @code{ENDFILE}. Only the @samp{getline In most other @command{awk} implementations, or if @command{gawk} is in compatibility mode (@pxref{Options}), they are not special. -@c FIXME: For 4.1 maybe deal with this? +@c FIXME: For 4.2 maybe deal with this? @ignore Date: Tue, 17 May 2011 02:06:10 PDT From: rankin@pactechdata.com (Pat Rankin) @@ -12429,7 +12568,7 @@ An empty (i.e., nonexistent) pattern is considered to match @emph{every} input record. For example, the program: @example -awk '@{ print $1 @}' BBS-list +awk '@{ print $1 @}' mail-list @end example @noindent @@ -12682,6 +12821,7 @@ the first thing on its line. @subsection The @code{while} Statement @cindex @code{while} statement @cindex loops +@cindex loops, @code{while} @cindex loops, See Also @code{while} statement In programming, a @dfn{loop} is a part of a program that can @@ -12742,6 +12882,7 @@ program is harder to read without it. @node Do Statement @subsection The @code{do}-@code{while} Statement @cindex @code{do}-@code{while} statement +@cindex loops, @code{do}-@code{while} The @code{do} loop is a variation of the @code{while} looping statement. The @code{do} loop executes the @var{body} once and then repeats the @@ -12787,6 +12928,7 @@ occasionally is there a real use for a @code{do} statement. @node For Statement @subsection The @code{for} Statement @cindex @code{for} statement +@cindex loops, @code{for}, iterative The @code{for} statement makes it more convenient to count iterations of a loop. The general form of the @code{for} statement looks like this: @@ -12893,6 +13035,8 @@ for more information on this version of the @code{for} loop. @cindex @code{case} keyword @cindex @code{default} keyword +This @value{SECTION} describes a @command{gawk}-specific feature. + The @code{switch} statement allows the evaluation of an expression and the execution of statements based on a @code{case} match. Case statements are checked for a match in the order they are defined. If no suitable @@ -12957,6 +13101,7 @@ it is not available. @subsection The @code{break} Statement @cindex @code{break} statement @cindex loops, exiting +@cindex loops, @code{break} statement and The @code{break} statement jumps out of the innermost @code{for}, @code{while}, or @code{do} loop that encloses it. The following example @@ -13016,6 +13161,7 @@ This is discussed in @ref{Switch Statement}. @cindex POSIX @command{awk}, @code{break} statement and @cindex dark corner, @code{break} statement @cindex @command{gawk}, @code{break} statement in +@cindex Brian Kernighan's @command{awk} The @code{break} statement has no meaning when used outside the body of a loop or @code{switch}. However, although it was never documented, @@ -13080,6 +13226,7 @@ This program loops forever once @code{x} reaches 5. @cindex POSIX @command{awk}, @code{continue} statement and @cindex dark corner, @code{continue} statement @cindex @command{gawk}, @code{continue} statement in +@cindex Brian Kernighan's @command{awk} The @code{continue} statement has no special meaning with respect to the @code{switch} statement, nor does it have any meaning when used outside the body of a loop. Historical versions of @command{awk} treated a @code{continue} @@ -13217,8 +13364,10 @@ See @uref{http://austingroupbugs.net/view.php?id=607, the Austin Group website}. @cindex functions, user-defined, @code{next}/@code{nextfile} statements and @cindex @code{nextfile} statement, user-defined functions and -The current version of the Brian Kernighan's @command{awk} (@pxref{Other -Versions}) also supports @code{nextfile}. However, it doesn't allow the +@cindex Brian Kernighan's @command{awk} +@cindex @command{mawk} utility +The current version of the Brian Kernighan's @command{awk}, and @command{mawk} (@pxref{Other +Versions}) also support @code{nextfile}. However, they don't allow the @code{nextfile} statement inside function bodies (@pxref{User-defined}). @command{gawk} does; a @code{nextfile} inside a function body reads the next record and starts processing it with the first rule in the program, @@ -13455,8 +13604,8 @@ is to simply say @samp{FS = FS}, perhaps with an explanatory comment. @cindex @command{gawk}, @code{IGNORECASE} variable in @cindex @code{IGNORECASE} variable @cindex differences in @command{awk} and @command{gawk}, @code{IGNORECASE} variable -@cindex case sensitivity, string comparisons and -@cindex case sensitivity, regexps and +@cindex case sensitivity, and string comparisons +@cindex case sensitivity, and regexps @cindex regular expressions, case sensitivity @item IGNORECASE # If @code{IGNORECASE} is nonzero or non-null, then all string comparisons @@ -13621,16 +13770,16 @@ In the following example: $ @kbd{awk 'BEGIN @{} > @kbd{for (i = 0; i < ARGC; i++)} > @kbd{print ARGV[i]} -> @kbd{@}' inventory-shipped BBS-list} +> @kbd{@}' inventory-shipped mail-list} @print{} awk @print{} inventory-shipped -@print{} BBS-list +@print{} mail-list @end example @noindent @code{ARGV[0]} contains @samp{awk}, @code{ARGV[1]} contains @samp{inventory-shipped}, and @code{ARGV[2]} contains -@samp{BBS-list}. The value of @code{ARGC} is three, one more than the +@samp{mail-list}. The value of @code{ARGC} is three, one more than the index of the last element in @code{ARGV}, because the elements are numbered from zero. @@ -13673,7 +13822,7 @@ or if @command{gawk} is in compatibility mode it is not special. @cindex @code{ENVIRON} array -@cindex environment variables +@cindex environment variables, in @code{ENVIRON} array @item ENVIRON An associative array containing the values of the environment. The array indices are the environment variable names; the elements are the values of @@ -13796,10 +13945,12 @@ The following elements (listed alphabetically) are guaranteed to be available: @table @code +@cindex effective group ID of @command{gawk} user @item PROCINFO["egid"] The value of the @code{getegid()} system call. @item PROCINFO["euid"] +@cindex effective user ID of @command{gawk} user The value of the @code{geteuid()} system call. @item PROCINFO["FS"] @@ -13809,6 +13960,7 @@ This is or @code{"FPAT"} if field matching with @code{FPAT} is in effect. @item PROCINFO["identifiers"] +@cindex program identifiers A subarray, indexed by the names of all identifiers used in the text of the AWK program. For each identifier, the value of the element is one of the following: @@ -13837,15 +13989,19 @@ after it has finished parsing the program; they are @emph{not} updated while the program runs. @item PROCINFO["gid"] +@cindex group ID of @command{gawk} user The value of the @code{getgid()} system call. @item PROCINFO["pgrpid"] +@cindex process group idIDof @command{gawk} process The process group ID of the current process. @item PROCINFO["pid"] +@cindex process ID of @command{gawk} process The process ID of the current process. @item PROCINFO["ppid"] +@cindex parent process ID of @command{gawk} process The parent process ID of the current process. @item PROCINFO["sorted_in"] @@ -13865,25 +14021,31 @@ Assigning a new value to this element changes the default. The value of the @code{getuid()} system call. @item PROCINFO["version"] +@cindex version of @command{gawk} +@cindex @command{gawk} version The version of @command{gawk}. @end table The following additional elements in the array are available to provide information about the MPFR and GMP libraries if your version of @command{gawk} supports arbitrary precision numbers -(@pxref{Arbitrary Precision Arithmetic}): +(@pxref{Gawk and MPFR}): @table @code +@cindex version of GNU MPFR library @item PROCINFO["mpfr_version"] The version of the GNU MPFR library. @item PROCINFO["gmp_version"] +@cindex version of GNU MP library The version of the GNU MP library. @item PROCINFO["prec_max"] +@cindex maximum precision supported by MPFR library The maximum precision supported by MPFR. @item PROCINFO["prec_min"] +@cindex minimum precision supported by MPFR library The minimum precision required by MPFR. @end table @@ -13894,12 +14056,15 @@ of @command{gawk} supports dynamic loading of extension functions @table @code @item PROCINFO["api_major"] +@cindex version of @command{gawk} extension API +@cindex extension API, version number The major version of the extension API. @item PROCINFO["api_minor"] The minor version of the extension API. @end table +@cindex supplementary groups of @command{gawk} process On some systems, there may be elements in the array, @code{"group1"} through @code{"group@var{N}"} for some @var{N}. @var{N} is the number of supplementary groups that the process has. Use the @code{in} operator @@ -13907,7 +14072,7 @@ to test for these elements (@pxref{Reference to Elements}). @cindex @command{gawk}, @code{PROCINFO} array in -@cindex @code{PROCINFO} array +@cindex @code{PROCINFO} array, uses The @code{PROCINFO} array has the following additional uses: @itemize @bullet @@ -13979,7 +14144,7 @@ if an element in @code{SYMTAB} is an array. Also, you may not use the @code{delete} statement with the @code{SYMTAB} array. -You may use an index for @code{SYMTAB} that is not a predefined identifer: +You may use an index for @code{SYMTAB} that is not a predefined identifier: @example SYMTAB["xxx"] = 5 @@ -14093,7 +14258,7 @@ changed. @node ARGC and ARGV @subsection Using @code{ARGC} and @code{ARGV} -@cindex @code{ARGC}/@code{ARGV} variables +@cindex @code{ARGC}/@code{ARGV} variables, how to use @cindex arguments, command-line @cindex command line, arguments @@ -14105,16 +14270,16 @@ and @code{ARGV}: $ @kbd{awk 'BEGIN @{} > @kbd{for (i = 0; i < ARGC; i++)} > @kbd{print ARGV[i]} -> @kbd{@}' inventory-shipped BBS-list} +> @kbd{@}' inventory-shipped mail-list} @print{} awk @print{} inventory-shipped -@print{} BBS-list +@print{} mail-list @end example @noindent In this example, @code{ARGV[0]} contains @samp{awk}, @code{ARGV[1]} contains @samp{inventory-shipped}, and @code{ARGV[2]} contains -@samp{BBS-list}. +@samp{mail-list}. Notice that the @command{awk} program is not entered in @code{ARGV}. The other command-line options, with their arguments, are also not entered. This includes variable assignments done with the @option{-v} @@ -14238,7 +14403,7 @@ ability to support true multidimensional arrays. @cindex variables, names of @cindex functions, names of -@cindex arrays, names of +@cindex arrays, names of, and names of functions/variables @cindex names, arrays/variables @cindex namespace issues @command{awk} maintains a single set @@ -14414,10 +14579,9 @@ Here, the number @code{1} isn't double-quoted, since @command{awk} automatically converts it to a string. @cindex @command{gawk}, @code{IGNORECASE} variable in -@cindex @code{IGNORECASE} variable @cindex case sensitivity, array indices and -@cindex arrays, @code{IGNORECASE} variable and -@cindex @code{IGNORECASE} variable, array subscripts and +@cindex arrays, and @code{IGNORECASE} variable +@cindex @code{IGNORECASE} variable, and array indices The value of @code{IGNORECASE} has no effect upon array subscripting. The identical string value used to store an array element must be used to retrieve it. @@ -14433,8 +14597,9 @@ is independent of the number of elements in the array. @node Reference to Elements @subsection Referring to an Array Element -@cindex arrays, elements, referencing -@cindex elements in arrays +@cindex arrays, referencing elements +@cindex array members +@cindex elements of arrays The principal way to use an array is to refer to one of its elements. An array reference is an expression as follows: @@ -14451,11 +14616,16 @@ The value of the array reference is the current value of that array element. For example, @code{foo[4.3]} is an expression for the element of array @code{foo} at index @samp{4.3}. +@cindex arrays, unassigned elements +@cindex unassigned array elements +@cindex empty array elements A reference to an array element that has no recorded value yields a value of @code{""}, the null string. This includes elements that have not been assigned any value as well as elements that have been deleted (@pxref{Delete}). +@cindex non-existent array elements +@cindex arrays, elements that don't exist @quotation NOTE A reference to an element that does not exist @emph{automatically} creates that array element, with the null string as its value. (In some cases, @@ -14475,7 +14645,7 @@ if it didn't exist before! @end quotation @c @cindex arrays, @code{in} operator and -@cindex @code{in} operator +@cindex @code{in} operator, testing if array element exists To determine whether an element exists in an array at a certain index, use the following expression: @@ -14510,8 +14680,8 @@ if (frequencies[2] != "") @node Assigning Elements @subsection Assigning Array Elements -@cindex arrays, elements, assigning -@cindex elements in arrays, assigning +@cindex arrays, elements, assigning values +@cindex elements in arrays, assigning values Array elements can be assigned values just like @command{awk} variables: @@ -14528,6 +14698,7 @@ assign to that element of the array. @node Array Example @subsection Basic Array Example +@cindex arrays, an example of using The following program takes a list of lines, each beginning with a line number, and prints them out in order of line number. The line numbers @@ -14597,7 +14768,9 @@ END @{ @node Scanning an Array @subsection Scanning All Elements of an Array @cindex elements in arrays, scanning +@cindex scanning arrays @cindex arrays, scanning +@cindex loops, @code{for}, array scanning In programs that use arrays, it is often necessary to use a loop that executes once for each element of an array. In other languages, where @@ -14614,7 +14787,7 @@ for (@var{var} in @var{array}) @end example @noindent -@cindex @code{in} operator +@cindex @code{in} operator, use in loops This loop executes @var{body} once for each index in @var{array} that the program has previously used, with the variable @var{var} set to that index. @@ -14653,8 +14826,9 @@ END @{ @xref{Word Sorting}, for a more detailed example of this type. -@cindex arrays, elements, order of -@cindex elements in arrays, order of +@cindex arrays, elements, order of access by @code{in} operator +@cindex elements in arrays, order of access by @code{in} operator +@cindex @code{in} operator, order of array access The order in which elements of the array are accessed by this statement is determined by the internal arrangement of the array elements within @command{awk} and normally cannot be controlled or changed. This can lead to @@ -14672,6 +14846,8 @@ determines the order in which the array is traversed. This order is usually based on the internal implementation of arrays and will vary from one version of @command{awk} to the next. +@cindex array scanning order, controlling +@cindex controlling array scanning order Often, though, you may wish to do something simple, such as ``traverse the array by comparing the indices in ascending order,'' or ``traverse the array by comparing the values in descending order.'' @@ -14688,6 +14864,7 @@ to use for comparison of array elements. This advanced feature is described later, in @ref{Array Sorting}. @end itemize +@cindex @code{PROCINFO}, values of @code{sorted_in} The following special values for @code{PROCINFO["sorted_in"]} are available: @table @code @@ -14848,7 +15025,7 @@ if (4 in foo) print "This will never be printed" @end example -@cindex null strings, array elements and +@cindex null strings, and deleting array elements It is important to note that deleting an element is @emph{not} the same as assigning it a null value (the empty string, @code{""}). For example: @@ -14870,6 +15047,7 @@ is not in the array is deleted. @cindex extensions, common@comma{} @code{delete} to delete entire arrays @cindex arrays, deleting entire contents @cindex deleting entire arrays +@cindex @code{delete} @var{array} @cindex differences in @command{awk} and @command{gawk}, array elements, deleting All the elements of an array may be deleted with a single statement by leaving off the subscript in the @code{delete} statement, @@ -14884,6 +15062,7 @@ Using this version of the @code{delete} statement is about three times more efficient than the equivalent loop that deletes each element one at a time. +@cindex Brian Kernighan's @command{awk} @quotation NOTE For many years, using @code{delete} without a subscript was a @command{gawk} extension. @@ -14926,9 +15105,9 @@ a = 3 @section Using Numbers to Subscript Arrays @cindex numbers, as array subscripts -@cindex arrays, subscripts +@cindex arrays, numeric subscripts @cindex subscripts in arrays, numbers as -@cindex @code{CONVFMT} variable, array subscripts and +@cindex @code{CONVFMT} variable, and array subscripts An important aspect to remember about arrays is that @emph{array subscripts are always strings}. When a numeric value is used as a subscript, it is converted to a string value before being used for subscripting @@ -14958,7 +15137,8 @@ string value from @code{xyz}---this time @code{"12.15"}---because the value of @code{CONVFMT} only allows two significant digits. This test fails, since @code{"12.15"} is different from @code{"12.153"}. -@cindex converting, during subscripting +@cindex converting integer array subscripts +@cindex integer array indices According to the rules for conversions (@pxref{Conversion}), integer values are always converted to strings as integers, no matter what the @@ -15064,7 +15244,7 @@ languages, including @command{awk}) to refer to an element of a two-dimensional array named @code{grid} is with @code{grid[@var{x},@var{y}]}. -@cindex @code{SUBSEP} variable, multidimensional arrays +@cindex @code{SUBSEP} variable, and multidimensional arrays Multidimensional arrays are supported in @command{awk} through concatenation of indices into one string. @command{awk} converts the indices into strings @@ -15096,6 +15276,7 @@ combined strings that are ambiguous. Suppose that @code{SUBSEP} is "b@@c"]}} are indistinguishable because both are actually stored as @samp{foo["a@@b@@c"]}. +@cindex @code{in} operator, index existence in multidimensional arrays To test whether a particular index sequence exists in a multidimensional array, use the same operator (@code{in}) that is used for single dimensional arrays. Write the whole sequence of indices @@ -15161,6 +15342,7 @@ multidimensional @emph{way of accessing} an array. @cindex subscripts in arrays, multidimensional, scanning @cindex arrays, multidimensional, scanning +@cindex scanning multidimensional arrays However, if your program has an array that is always accessed as multidimensional, you can get the effect of scanning it by combining the scanning @code{for} statement @@ -15202,6 +15384,7 @@ separate indices is recovered. @node Arrays of Arrays @section Arrays of Arrays +@cindex arrays of arrays @command{gawk} goes beyond standard @command{awk}'s multidimensional array access and provides true arrays of @@ -15461,6 +15644,7 @@ two arguments 11 and 10. @node Numeric Functions @subsection Numeric Functions +@cindex numeric functions The following list describes all of the built-in functions that work with numbers. @@ -15468,22 +15652,26 @@ Optional parameters are enclosed in square brackets@w{ ([ ]):} @table @code @item atan2(@var{y}, @var{x}) -@cindex @code{atan2()} function +@cindexawkfunc{atan2} +@cindex arctangent Return the arctangent of @code{@var{y} / @var{x}} in radians. You can use @samp{pi = atan2(0, -1)} to retrieve the value of @value{PI}. @item cos(@var{x}) -@cindex @code{cos()} function +@cindexawkfunc{cos} +@cindex cosine Return the cosine of @var{x}, with @var{x} in radians. @item exp(@var{x}) -@cindex @code{exp()} function +@cindexawkfunc{exp} +@cindex exponent Return the exponential of @var{x} (@code{e ^ @var{x}}) or report an error if @var{x} is out of range. The range of values @var{x} can have depends on your machine's floating-point representation. @item int(@var{x}) -@cindex @code{int()} function +@cindexawkfunc{int} +@cindex round to nearest integer Return the nearest integer to @var{x}, located between @var{x} and zero and truncated toward zero. @@ -15491,12 +15679,13 @@ For example, @code{int(3)} is 3, @code{int(3.9)} is 3, @code{int(-3.9)} is @minus{}3, and @code{int(-3)} is @minus{}3 as well. @item log(@var{x}) -@cindex @code{log()} function +@cindexawkfunc{log} +@cindex logarithm Return the natural logarithm of @var{x}, if @var{x} is positive; otherwise, report an error. @item rand() -@cindex @code{rand()} function +@cindexawkfunc{rand} @cindex random numbers, @code{rand()}/@code{srand()} functions Return a random number. The values of @code{rand()} are uniformly distributed between zero and one. @@ -15538,7 +15727,7 @@ function roll(n) @{ return 1 + int(rand() * n) @} @} @end example -@cindex numbers, random +@cindex seeding random number generator @cindex random numbers, seed of @quotation CAUTION In most @command{awk} implementations, including @command{gawk}, @@ -15554,17 +15743,19 @@ use @code{srand()}. @end quotation @item sin(@var{x}) -@cindex @code{sin()} function +@cindexawkfunc{sin} +@cindex sine Return the sine of @var{x}, with @var{x} in radians. @item sqrt(@var{x}) -@cindex @code{sqrt()} function +@cindexawkfunc{sqrt} +@cindex square root Return the positive square root of @var{x}. @command{gawk} prints a warning message if @var{x} is negative. Thus, @code{sqrt(4)} is 2. @item srand(@r{[}@var{x}@r{]}) -@cindex @code{srand()} function +@cindexawkfunc{srand} Set the starting point, or seed, for generating random numbers to the value @var{x}. @@ -15594,6 +15785,7 @@ sequences of random numbers. @node String Functions @subsection String-Manipulation Functions +@cindex string-manipulation functions The functions in this @value{SECTION} look at or change the text of one or more strings. @@ -15622,11 +15814,11 @@ pound sign@w{ (@samp{#}):} @table @code @item asort(@var{source} @r{[}, @var{dest} @r{[}, @var{how} @r{]} @r{]}) # @itemx asorti(@var{source} @r{[}, @var{dest} @r{[}, @var{how} @r{]} @r{]}) # -@cindex @code{asorti()} function (@command{gawk}) +@cindexgawkfunc{asorti} +@cindex sort array @cindex arrays, elements, retrieving number of -@cindex @code{asort()} function (@command{gawk}) -@cindex @command{gawk}, @code{IGNORECASE} variable in -@cindex @code{IGNORECASE} variable +@cindexgawkfunc{asort} +@cindex sort array indices These two functions are similar in behavior, so they are described together. @@ -15644,7 +15836,9 @@ sequential integers starting with one. If the optional array @var{dest} is specified, then @var{source} is duplicated into @var{dest}. @var{dest} is then sorted, leaving the indices of @var{source} unchanged. -When comparing strings, @code{IGNORECASE} affects the sorting. If the +@cindex @command{gawk}, @code{IGNORECASE} variable in +When comparing strings, @code{IGNORECASE} affects the sorting +(@pxref{Array Sorting Functions}). If the @var{source} array contains subarrays as values (@pxref{Arrays of Arrays}), they will come last, after all scalar values. @@ -15687,7 +15881,9 @@ a[3] = "middle" are not available in compatibility mode (@pxref{Options}). @item gensub(@var{regexp}, @var{replacement}, @var{how} @r{[}, @var{target}@r{]}) # -@cindex @code{gensub()} function (@command{gawk}) +@cindexgawkfunc{gensub} +@cindex search and replace in strings +@cindex substitute in string Search the target string @var{target} for matches of the regular expression @var{regexp}. If @var{how} is a string beginning with @samp{g} or @samp{G} (short for ``global''), then replace all matches of @var{regexp} with @@ -15696,7 +15892,7 @@ which match of @var{regexp} to replace. If no @var{target} is supplied, use @code{$0}. It returns the modified string as the result of the function and the original target string is @emph{not} changed. -@code{gensub()} is a general substitution function. It's purpose is +@code{gensub()} is a general substitution function. Its purpose is to provide more features than the standard @code{sub()} and @code{gsub()} functions. @@ -15750,7 +15946,7 @@ is the original unchanged value of @var{target}. in compatibility mode (@pxref{Options}). @item gsub(@var{regexp}, @var{replacement} @r{[}, @var{target}@r{]}) -@cindex @code{gsub()} function +@cindexawkfunc{gsub} Search @var{target} for @emph{all} of the longest, leftmost, @emph{nonoverlapping} matching substrings it can find and replace them with @var{replacement}. @@ -15772,8 +15968,9 @@ As in @code{sub()}, the characters @samp{&} and @samp{\} are special, and the third argument must be assignable. @item index(@var{in}, @var{find}) -@cindex @code{index()} function -@cindex searching +@cindexawkfunc{index} +@cindex search in string +@cindex find substring in string Search the string @var{in} for the first occurrence of the string @var{find}, and return the position in characters where that occurrence begins in the string @var{in}. Consider the following example: @@ -15790,7 +15987,9 @@ If @var{find} is not found, @code{index()} returns zero. It is a fatal error to use a regexp constant for @var{find}. @item length(@r{[}@var{string}@r{]}) -@cindex @code{length()} function +@cindexawkfunc{length} +@cindex string length +@cindex length of string Return the number of characters in @var{string}. If @var{string} is a number, the length of the digit string representing that number is returned. For example, @code{length("abcde")} is five. By @@ -15798,6 +15997,8 @@ contrast, @code{length(15 * 35)} works out to three. In this example, 15 * 35 = 525, and 525 is then converted to the string @code{"525"}, which has three characters. +@cindex length of input record +@cindex input record, length of If no argument is supplied, @code{length()} returns the length of @code{$0}. @c @cindex historical features @@ -15836,6 +16037,8 @@ warning about this. @cindex common extensions, @code{length()} applied to an array @cindex extensions, common@comma{} @code{length()} applied to an array @cindex differences between @command{gawk} and @command{awk} +@cindex number of array elements +@cindex array, number of elements With @command{gawk} and several other @command{awk} implementations, when given an array argument, the @code{length()} function returns the number of elements in the array. @value{COMMONEXT} @@ -15849,7 +16052,9 @@ If @option{--posix} is supplied, using an array argument is a fatal error (@pxref{Arrays}). @item match(@var{string}, @var{regexp} @r{[}, @var{array}@r{]}) -@cindex @code{match()} function +@cindexawkfunc{match} +@cindex string, regular expression match +@cindex match regexp in string Search @var{string} for the longest, leftmost substring matched by the regular expression, @var{regexp} and return the character position, or @dfn{index}, @@ -15964,7 +16169,8 @@ The @var{array} argument to @code{match()} is a using a third argument is a fatal error. @item patsplit(@var{string}, @var{array} @r{[}, @var{fieldpat} @r{[}, @var{seps} @r{]} @r{]}) # -@cindex @code{patsplit()} function (@command{gawk}) +@cindexgawkfunc{patsplit} +@cindex split string into array Divide @var{string} into pieces defined by @var{fieldpat} and store the pieces in @var{array} and the separator strings in the @@ -15995,7 +16201,7 @@ The @code{patsplit()} function is a it is not available. @item split(@var{string}, @var{array} @r{[}, @var{fieldsep} @r{[}, @var{seps} @r{]} @r{]}) -@cindex @code{split()} function +@cindexawkfunc{split} Divide @var{string} into pieces separated by @var{fieldsep} and store the pieces in @var{array} and the separator strings in the @var{seps} array. The first piece is stored in @@ -16024,7 +16230,7 @@ split("cul-de-sac", a, "-", seps) @end example @noindent -@cindex strings, splitting +@cindex strings splitting, example splits the string @samp{cul-de-sac} into three fields using @samp{-} as the separator. It sets the contents of the array @code{a} as follows: @@ -16080,7 +16286,8 @@ If @var{string} does not match @var{fieldsep} at all (but is not null), @var{string}. @item sprintf(@var{format}, @var{expression1}, @dots{}) -@cindex @code{sprintf()} function +@cindexawkfunc{sprintf} +@cindex formatting strings Return (without printing) the string that @code{printf} would have printed out with the same arguments (@pxref{Printf}). @@ -16093,7 +16300,8 @@ pival = sprintf("pi = %.2f (approx.)", 22/7) @noindent assigns the string @w{@samp{pi = 3.14 (approx.)}} to the variable @code{pival}. -@cindex @code{strtonum()} function (@command{gawk}) +@cindexgawkfunc{strtonum} +@cindex convert string to number @item strtonum(@var{str}) # Examine @var{str} and return its numeric value. If @var{str} begins with a leading @samp{0}, @code{strtonum()} assumes that @var{str} @@ -16116,12 +16324,12 @@ you use the @option{--non-decimal-data} option, which isn't recommended. Note also that @code{strtonum()} uses the current locale's decimal point for recognizing numbers (@pxref{Locales}). -@cindex differences in @command{awk} and @command{gawk}, @code{strtonum()} function (@command{gawk}) @code{strtonum()} is a @command{gawk} extension; it is not available in compatibility mode (@pxref{Options}). @item sub(@var{regexp}, @var{replacement} @r{[}, @var{target}@r{]}) -@cindex @code{sub()} function +@cindexawkfunc{sub} +@cindex replace in string Search @var{target}, which is treated as a string, for the leftmost, longest substring matched by the regular expression @var{regexp}. Modify the entire string @@ -16221,7 +16429,8 @@ Finally, if the @var{regexp} is not a regexp constant, it is converted into a string, and then the value of that string is treated as the regexp to match. @item substr(@var{string}, @var{start} @r{[}, @var{length}@r{]}) -@cindex @code{substr()} function +@cindexawkfunc{substr} +@cindex substring Return a @var{length}-character-long substring of @var{string}, starting at character number @var{start}. The first character of a string is character number one.@footnote{This is different from @@ -16235,6 +16444,7 @@ suffix is also returned if @var{length} is greater than the number of characters remaining in the string, counting from character @var{start}. +@cindex Brian Kernighan's @command{awk} If @var{start} is less than one, @code{substr()} treats it as if it was one. (POSIX doesn't specify what to do in this case: Brian Kernighan's @command{awk} acts this way, and therefore @command{gawk} @@ -16277,16 +16487,18 @@ string = substr(string, 1, 2) "CDE" substr(string, 6) @end example @cindex case sensitivity, converting case -@cindex converting, case +@cindex strings, converting letter case @item tolower(@var{string}) -@cindex @code{tolower()} function +@cindexawkfunc{tolower} +@cindex convert string to lower case Return a copy of @var{string}, with each uppercase character in the string replaced with its corresponding lowercase character. Nonalphabetic characters are left unchanged. For example, @code{tolower("MiXeD cAsE 123")} returns @code{"mixed case 123"}. @item toupper(@var{string}) -@cindex @code{toupper()} function +@cindexawkfunc{toupper} +@cindex convert string to upper case Return a copy of @var{string}, with each lowercase character in the string replaced with its corresponding uppercase character. Nonalphabetic characters are left unchanged. For example, @@ -16314,6 +16526,7 @@ and builds an internal copy of it that can be executed. Then there is the runtime level, which is when @command{awk} actually scans the replacement string to determine what to generate. +@cindex Brian Kernighan's @command{awk} At both levels, @command{awk} looks for a defined set of characters that can come after a backslash. At the lexical level, it looks for the escape sequences listed in @ref{Escape Sequences}. @@ -16711,14 +16924,16 @@ Although this makes a certain amount of sense, it can be surprising. @node I/O Functions @subsection Input/Output Functions +@cindex input/output functions The following functions relate to input/output (I/O). Optional parameters are enclosed in square brackets ([ ]): @table @code @item close(@var{filename} @r{[}, @var{how}@r{]}) -@cindex @code{close()} function +@cindexawkfunc{close} @cindex files, closing +@cindex close file or coprocess Close the file @var{filename} for input or output. Alternatively, the argument may be a shell command that was used for creating a coprocess, or for redirecting to or from a pipe; then the coprocess or pipe is closed. @@ -16735,7 +16950,8 @@ not matter. which discusses this feature in more detail and gives an example. @item fflush(@r{[}@var{filename}@r{]}) -@cindex @code{fflush()} function +@cindexawkfunc{fflush} +@cindex flush buffered output Flush any buffered output associated with @var{filename}, which is either a file opened for writing or a shell command for redirecting output to a pipe or coprocess. @@ -16753,11 +16969,12 @@ This is the purpose of the @code{fflush()} function---@command{gawk} also buffers its output and the @code{fflush()} function forces @command{gawk} to flush its buffers. -@code{fflush()} was added to Brian Kernighan's -version of @command{awk} in 1994. -For over two decades, it was not part of the POSIX standard. -As of December, 2012, it was accepted for -inclusion into the POSIX standard. +@cindex extensions, common@comma{} @code{fflush()} function +@cindex Brian Kernighan's @command{awk} +@code{fflush()} was added to Brian Kernighan's version of @command{awk} in +April of 1992. For two decades, it was not part of the POSIX standard. +As of December, 2012, it was accepted for inclusion into the POSIX +standard. See @uref{http://austingroupbugs.net/view.php?id=634, the Austin Group website}. POSIX standardizes @code{fflush()} as follows: If there @@ -16793,7 +17010,8 @@ or if @var{filename} is not an open file, pipe, or coprocess. In such a case, @code{fflush()} returns @minus{}1, as well. @item system(@var{command}) -@cindex @code{system()} function +@cindexawkfunc{system} +@cindex invoke shell command @cindex interacting with other programs Execute the operating-system command @var{command} and then return to the @command{awk} program. @@ -17068,6 +17286,7 @@ you would see the latter (undesirable) output. @node Time Functions @subsection Time Functions +@cindex time functions @c STARTOFRANGE tst @cindex timestamps @@ -17087,7 +17306,18 @@ it is the number of seconds since 1970-01-01 00:00:00 UTC, not counting leap seconds.@footnote{@xref{Glossary}, especially the entries ``Epoch'' and ``UTC.''} All known POSIX-compliant systems support timestamps from 0 through -@math{2^{31} - 1}, which is sufficient to represent times through +@iftex +@math{2^{31} - 1}, +@end iftex +@ifnottex +@ifnotdocbook +2^31 - 1, +@end ifnotdocbook +@end ifnottex +@docbook +2<superscript>31</superscript> − 1, @c +@end docbook +which is sufficient to represent times through 2038-01-19 03:14:07 UTC. Many systems support a wider range of timestamps, including negative timestamps that represent times before the epoch. @@ -17106,7 +17336,8 @@ Optional parameters are enclosed in square brackets ([ ]): @table @code @item mktime(@var{datespec}) -@cindex @code{mktime()} function (@command{gawk}) +@cindexgawkfunc{mktime} +@cindex generate time values Turn @var{datespec} into a timestamp in the same form as is returned by @code{systime()}. It is similar to the function of the same name in ISO C. The argument, @var{datespec}, is a string of the form @@ -17136,7 +17367,8 @@ is out of range, @code{mktime()} returns @minus{}1. @cindex @code{PROCINFO} array @item strftime(@r{[}@var{format} @r{[}, @var{timestamp} @r{[}, @var{utc-flag}@r{]]]}) @c STARTOFRANGE strf -@cindex @code{strftime()} function (@command{gawk}) +@cindexgawkfunc{strftime} +@cindex format time string Format the time specified by @var{timestamp} based on the contents of the @var{format} string and return the result. It is similar to the function of the same name in ISO C. @@ -17153,11 +17385,12 @@ The default string value is @code{@w{"%a %b %e %H:%M:%S %Z %Y"}}. This format string produces output that is equivalent to that of the @command{date} utility. You can assign a new value to @code{PROCINFO["strftime"]} to -change the default format. +change the default format; see below for the various format directives. @item systime() -@cindex @code{systime()} function (@command{gawk}) +@cindexgawkfunc{systime} @cindex timestamps +@cindex current system time Return the current time as the number of seconds since the system epoch. On POSIX systems, this is the number of seconds since 1970-01-01 00:00:00 UTC, not counting leap seconds. @@ -17451,6 +17684,7 @@ gawk 'BEGIN @{ @node Bitwise Functions @subsection Bit-Manipulation Functions +@cindex bit-manipulation functions @c STARTOFRANGE bit @cindex bitwise, operations @c STARTOFRANGE and @@ -17613,27 +17847,33 @@ bitwise operations just described. They are: @cindex @command{gawk}, bitwise operations in @table @code -@cindex @code{and()} function (@command{gawk}) +@cindexgawkfunc{and} +@cindex bitwise AND @item and(@var{v1}, @var{v2} @r{[}, @r{@dots{}]}) Return the bitwise AND of the arguments. There must be at least two. -@cindex @code{compl()} function (@command{gawk}) +@cindexgawkfunc{compl} +@cindex bitwise complement @item compl(@var{val}) Return the bitwise complement of @var{val}. -@cindex @code{lshift()} function (@command{gawk}) +@cindexgawkfunc{lshift} +@cindex left shift @item lshift(@var{val}, @var{count}) Return the value of @var{val}, shifted left by @var{count} bits. -@cindex @code{or()} function (@command{gawk}) +@cindexgawkfunc{or} +@cindex bitwise OR @item or(@var{v1}, @var{v2} @r{[}, @r{@dots{}]}) Return the bitwise OR of the arguments. There must be at least two. -@cindex @code{rshift()} function (@command{gawk}) +@cindexgawkfunc{rshift} +@cindex right shift @item rshift(@var{val}, @var{count}) Return the value of @var{val}, shifted right by @var{count} bits. -@cindex @code{xor()} function (@command{gawk}) +@cindexgawkfunc{xor} +@cindex bitwise XOR @item xor(@var{v1}, @var{v2} @r{[}, @r{@dots{}]}) Return the bitwise XOR of the arguments. There must be at least two. @end table @@ -17725,6 +17965,7 @@ $ @kbd{gawk -f testbits.awk} @cindex strings, converting @cindex numbers, converting @cindex converting, numbers to strings +@cindex number as string of bits The @code{bits2str()} function turns a binary number into a string. The number @code{1} represents a binary value where the rightmost bit is set to 1. Using this mask, @@ -17760,7 +18001,8 @@ that traverses every element of a true multidimensional array (@pxref{Arrays of Arrays}). @table @code -@cindex @code{isarray()} function (@command{gawk}) +@cindexgawkfunc{isarray} +@cindex scalar or array @item isarray(@var{x}) Return a true value if @var{x} is an array. Otherwise return false. @end table @@ -17768,7 +18010,7 @@ Return a true value if @var{x} is an array. Otherwise return false. @code{isarray()} is meant for use in two circumstances. The first is when traversing a multidimensional array: you can test if an element is itself an array or not. The second is inside the body of a user-defined function -(not discussed yet; @pxref{User-defined}), to test if a paramater is an +(not discussed yet; @pxref{User-defined}), to test if a parameter is an array or not. Note, however, that using @code{isarray()} at the global level to test @@ -17782,6 +18024,7 @@ will end up turning it into a scalar. @subsection String-Translation Functions @cindex @command{gawk}, string-translation functions @cindex functions, string-translation +@cindex string-translation functions @cindex internationalization @cindex @command{awk} programs, internationalizing @@ -17793,7 +18036,8 @@ for the full story. Optional parameters are enclosed in square brackets ([ ]): @table @code -@cindex @code{bindtextdomain()} function (@command{gawk}) +@cindexgawkfunc{bindtextdomain} +@cindex set directory of message catalogs @item bindtextdomain(@var{directory} @r{[}, @var{domain}@r{]}) Set the directory in which @command{gawk} will look for message translation files, in case they @@ -17806,14 +18050,15 @@ If @var{directory} is the null string (@code{""}), then @code{bindtextdomain()} returns the current binding for the given @var{domain}. -@cindex @code{dcgettext()} function (@command{gawk}) +@cindexgawkfunc{dcgettext} +@cindex translate string @item dcgettext(@var{string} @r{[}, @var{domain} @r{[}, @var{category}@r{]]}) Return the translation of @var{string} in text domain @var{domain} for locale category @var{category}. The default value for @var{domain} is the current value of @code{TEXTDOMAIN}. The default value for @var{category} is @code{"LC_MESSAGES"}. -@cindex @code{dcngettext()} function (@command{gawk}) +@cindexgawkfunc{dcngettext} @item dcngettext(@var{string1}, @var{string2}, @var{number} @r{[}, @var{domain} @r{[}, @var{category}@r{]]}) Return the plural form used for @var{number} of the translation of @var{string1} and @var{string2} in text domain @@ -17830,7 +18075,7 @@ The default value for @var{category} is @code{"LC_MESSAGES"}. @section User-Defined Functions @c STARTOFRANGE udfunc -@cindex user-defined, functions +@cindex user-defined functions @c STARTOFRANGE funcud @cindex functions, user-defined Complicated @command{awk} programs can often be simplified by defining @@ -17889,7 +18134,7 @@ have a parameter with the same name as the function itself. In addition, according to the POSIX standard, function parameters cannot have the same name as one of the special built-in variables (@pxref{Built-in Variables}. Not all versions of @command{awk} -enforce this restriction. +enforce this restriction.) The @var{body-of-function} consists of @command{awk} statements. It is the most important part of the definition, because it says what the function @@ -17916,6 +18161,7 @@ conventional to place some extra space between the arguments and the local variables, in order to document how your function is supposed to be used. @cindex variables, shadowing +@cindex shadowing of variable values During execution of the function body, the arguments and local variable values hide, or @dfn{shadow}, any variables of the same names used in the rest of the program. The shadowed variables are not accessible in the @@ -17936,7 +18182,7 @@ function. When this happens, we say the function is @dfn{recursive}. The act of a function calling itself is called @dfn{recursion}. All the built-in functions return a value to their caller. -User-defined functions can do also, using the @code{return} statement, +User-defined functions can do so also, using the @code{return} statement, which is described in detail in @ref{Return Statement}. Many of the subsequent examples in this @value{SECTION} use the @code{return} statement. @@ -17974,6 +18220,7 @@ keyword @code{function} when defining a function. @node Function Example @subsection Function Definition Examples +@cindex function definition example Here is an example of a user-defined function, called @code{myprint()}, that takes a number and prints it in a specific format: @@ -18028,7 +18275,8 @@ Instead of having to repeat this loop everywhere that you need to clear out an array, your program can just call @code{delarray}. (This guarantees portability. The use of @samp{delete @var{array}} to delete -the contents of an entire array is a nonstandard extension.) +the contents of an entire array is a recent@footnote{Late in 2012.} +addition to the POSIX standard.) The following is an example of a recursive function. It takes a string as an input parameter and returns the string in backwards order. @@ -18084,7 +18332,10 @@ function ctime(ts, format) @subsection Calling User-Defined Functions @c STARTOFRANGE fudc -This section describes how to call a user-defined function. +@cindex functions, user-defined, calling +@dfn{Calling a function} means causing the function to run and do its job. +A function call is an expression and its value is the value returned by +the function. @menu * Calling A Function:: Don't use spaces. @@ -18095,11 +18346,6 @@ This section describes how to call a user-defined function. @node Calling A Function @subsubsection Writing A Function Call -@cindex functions, user-defined, calling -@dfn{Calling a function} means causing the function to run and do its job. -A function call is an expression and its value is the value returned by -the function. - A function call consists of the function name followed by the arguments in parentheses. @command{awk} expressions are what you write in the call for the arguments. Each time the call is executed, these @@ -18123,8 +18369,8 @@ an error. @node Variable Scope @subsubsection Controlling Variable Scope -@cindex local variables -@cindex variables, local +@cindex local variables, in a function +@cindex variables, local to a function There is no way to make a variable local to a @code{@{ @dots{} @}} block in @command{awk}, but you can make a variable local to a function. It is good practice to do so whenever a variable is needed only in that @@ -18569,7 +18815,7 @@ character: @example the_func = "sum" -result = @@the_func() # calls the `sum' function +result = @@the_func() # calls the sum() function @end example Here is a full program that processes the previously shown data, @@ -18690,8 +18936,9 @@ We can do something similar using @command{gawk}, like this: @ignore @c file eg/lib/quicksort.awk # -# Arnold Robbins, arnold@skeeve.com, Public Domain +# Arnold Robbins, arnold@@skeeve.com, Public Domain # January 2009 + @c endfile @end ignore @@ -18764,7 +19011,7 @@ or equal to), which yields data sorted in descending order. Next comes a sorting function. It is parameterized with the starting and ending field numbers and the comparison function. It builds an array with -the data and calls @code{quicksort} appropriately, and then formats the +the data and calls @code{quicksort()} appropriately, and then formats the results as a single string: @example @@ -18902,6 +19149,8 @@ it allows you to encapsulate algorithms and program tasks in a single place. It simplifies programming, making program development more manageable, and making programs more readable. +@cindex Kernighan, Brian +@cindex Plauger, P.J.@: In their seminal 1976 book, @cite{Software Tools},@footnote{Sadly, over 35 years later, many of the lessons taught by this book have yet to be learned by a vast number of practicing programmers.} Brian Kernighan @@ -19031,7 +19280,7 @@ with the user's program. @cindex underscore (@code{_}), in names of private variables In addition, several of the library functions use a prefix that helps indicate what function or set of functions use the variables---for example, -@code{_pw_byname} in the user database routines +@code{_pw_byname()} in the user database routines (@pxref{Passwd Functions}). This convention is recommended, since it even further decreases the chance of inadvertent conflict among variable names. Note that this @@ -19050,7 +19299,7 @@ The leading capital letter indicates that it is global, while the fact that the variable name is not all capital letters indicates that the variable is not one of @command{awk}'s built-in variables, such as @code{FS}. -@cindex @option{--dump-variables} option +@cindex @option{--dump-variables} option, using for library functions It is also important that @emph{all} variables in library functions that do not need to save state are, in fact, declared local.@footnote{@command{gawk}'s @option{--dump-variables} command-line @@ -19345,9 +19594,9 @@ with an @code{exit} statement. The way @code{printf} and @code{sprintf()} (@pxref{Printf}) perform rounding often depends upon the system's C @code{sprintf()} -subroutine. On many machines, @code{sprintf()} rounding is ``unbiased,'' -which means it doesn't always round a trailing @samp{.5} up, contrary -to naive expectations. In unbiased rounding, @samp{.5} rounds to even, +subroutine. On many machines, @code{sprintf()} rounding is @dfn{unbiased}, +which means it doesn't always round a trailing .5 up, contrary +to naive expectations. In unbiased rounding, .5 rounds to even, rather than always up, so 1.5 rounds to 2 but 4.5 rounds to 4. This means that if you are using a format that does rounding (e.g., @code{"%.0f"}), you should check what your system does. The following function does @@ -19396,7 +19645,7 @@ function round(x, ival, aval, fraction) @c don't include test harness in the file that gets installed # test harness -@{ print $0, round($0) @} +# @{ print $0, round($0) @} @end example @node Cliff Random Function @@ -19463,6 +19712,7 @@ reason to build them into the @command{awk} interpreter: @cindex @code{ord()} user-defined function @cindex @code{chr()} user-defined function +@cindex @code{_ord_init()} user-defined function @example @c file eg/lib/ord.awk # ord.awk --- do ord and chr @@ -19509,8 +19759,9 @@ function _ord_init( low, high, i, t) @cindex character sets (machine character encodings) @cindex ASCII @cindex EBCDIC +@cindex Unicode @cindex mark parity -Some explanation of the numbers used by @code{chr()} is worthwhile. +Some explanation of the numbers used by @code{_ord_init()} is worthwhile. The most prominent character set in use today is ASCII.@footnote{This is changing; many systems use Unicode, a very large character set that includes ASCII as a subset. On systems with full Unicode support, @@ -19521,7 +19772,7 @@ Although an defines characters that use the values from 0 to 127.@footnote{ASCII has been extended in many countries to use the values from 128 to 255 for country-specific characters. If your system uses these extensions, -you can simplify @code{_ord_init} to loop from 0 to 255.} +you can simplify @code{_ord_init()} to loop from 0 to 255.} In the now distant past, at least one minicomputer manufacturer @c Pr1me, blech @@ -20195,7 +20446,7 @@ END @{ Occasionally, you might not want @command{awk} to process command-line variable assignments (@pxref{Assignment Options}). -In particular, if you have a file name that contain an @samp{=} character, +In particular, if you have a file name that contains an @samp{=} character, @command{awk} treats the file name as an assignment, and does not process it. Some users have suggested an additional command-line option for @command{gawk} @@ -20865,7 +21116,7 @@ from anywhere within a user's program, and the user may have his or her own way of splitting records and fields. -@cindex @code{PROCINFO} array +@cindex @code{PROCINFO} array, testing the field splitting The @code{using_fw} variable checks @code{PROCINFO["FS"]}, which is @code{"FIELDWIDTHS"} if field splitting is being done with @code{FIELDWIDTHS}. This makes it possible to restore the correct @@ -20874,7 +21125,7 @@ field-splitting mechanism later. The test can only be true for or on some other @command{awk} implementation. The code that checks for using @code{FPAT}, using @code{using_fpat} -and @code{PROCINFO["FS"]} is similar. +and @code{PROCINFO["FS"]}, is similar. The main part of the function uses a loop to read database lines, split the line into fields, and then store the line into each array as necessary. @@ -20904,10 +21155,9 @@ function getpwnam(name) @end example @cindex @code{getpwuid()} function (C library) -Similarly, -the @code{getpwuid} function takes a user ID number argument. If that -user number is in the database, it returns the appropriate line. Otherwise, it -returns the null string: +Similarly, the @code{getpwuid()} function takes a user ID number +argument. If that user number is in the database, it returns the +appropriate line. Otherwise, it returns the null string: @cindex @code{getpwuid()} user-defined function @example @@ -20989,7 +21239,7 @@ uses these functions. @cindex group database, reading @c STARTOFRANGE datagr @cindex database, group, reading -@cindex @code{PROCINFO} array +@cindex @code{PROCINFO} array, and group membership @cindex @code{getgrent()} function (C library) @cindex @code{getgrent()} user-defined function @cindex groups@comma{} information about @@ -21411,7 +21661,7 @@ index and value, use the indirect function call syntax and the value. When calling @code{walk_array()}, you would pass the name of a user-defined -function that expects to receive and index and a value, and then processes +function that expects to receive an index and a value, and then processes the element. @@ -21765,7 +22015,7 @@ complete field list, including filler fields: @example @c file eg/prog/cut.awk -function set_charlist( field, i, j, f, g, t, +function set_charlist( field, i, j, f, g, n, m, t, filler, last, len) @{ field = 1 # count total fields @@ -21862,6 +22112,7 @@ of picking the input line apart by characters. @cindex searching, files for regular expressions @c STARTOFRANGE fsregexp @cindex files, searching for regular expressions +@c STARTOFRANGE egrep @cindex @command{egrep} utility The @command{egrep} utility searches files for patterns. It uses regular expressions that are almost identical to those available in @command{awk} @@ -22147,12 +22398,14 @@ or not. @c ENDOFRANGE regexps @c ENDOFRANGE sfregexp @c ENDOFRANGE fsregexp +@c ENDOFRANGE egrep @node Id Program @subsection Printing out User Information @cindex printing, user information @cindex users, information about, printing +@c STARTOFRANGE id @cindex @command{id} utility The @command{id} utility lists a user's real and effective user ID numbers, real and effective group ID numbers, and the user's group set, if any. @@ -22165,7 +22418,7 @@ $ @kbd{id} @print{} uid=500(arnold) gid=500(arnold) groups=6(disk),7(lp),19(floppy) @end example -@cindex @code{PROCINFO} array +@cindex @code{PROCINFO} array, and user and group ID numbers This information is part of what is provided by @command{gawk}'s @code{PROCINFO} array (@pxref{Built-in Variables}). However, the @command{id} utility provides a more palatable output than just @@ -22266,7 +22519,6 @@ BEGIN \ @c endfile @end example -@cindex @code{in} operator The test in the @code{for} loop is worth noting. Any supplementary groups in the @code{PROCINFO} array have the indices @code{"group1"} through @code{"group@var{N}"} for some @@ -22276,7 +22528,7 @@ there are. This loop works by starting at one, concatenating the value with @code{"group"}, and then using @code{in} to see if that value is -in the array. Eventually, @code{i} is incremented past +in the array (@pxref{Reference to Elements}). Eventually, @code{i} is incremented past the last group in the array and the loop exits. The loop is also correct if there are @emph{no} supplementary @@ -22289,6 +22541,7 @@ The POSIX version of @command{id} takes arguments that control which information is printed. Modify this version to accept the same arguments and perform in the same way. @end ignore +@c ENDOFRANGE id @node Split Program @subsection Splitting a Large File into Pieces @@ -22297,6 +22550,7 @@ arguments and perform in the same way. @c STARTOFRANGE filspl @cindex files, splitting +@c STARTOFRANGE split @cindex @code{split} utility The @command{split} program splits large text files into smaller pieces. Usage is as follows:@footnote{This is the traditional usage. The @@ -22440,12 +22694,14 @@ which isn't true for EBCDIC systems. @c Exercise: Fix these problems. @c BFD... @c ENDOFRANGE filspl +@c ENDOFRANGE split @node Tee Program @subsection Duplicating Output into Multiple Files @cindex files, multiple@comma{} duplicating output into @cindex output, duplicating into files +@c STARTOFRANGE tee @cindex @code{tee} utility The @code{tee} program is known as a ``pipe fitting.'' @code{tee} copies its standard input to its standard output and also duplicates it to the @@ -22560,6 +22816,7 @@ END \ @} @c endfile @end example +@c ENDOFRANGE tee @node Uniq Program @subsection Printing Nonduplicated Lines of Text @@ -22570,6 +22827,7 @@ END \ @cindex printing, unduplicated lines of text @c STARTOFRANGE tpul @cindex text@comma{} printing, unduplicated lines of +@c STARTOFRANGE uniq @cindex @command{uniq} utility The @command{uniq} utility reads sorted lines of data on its standard input, and by default removes duplicate lines. In other words, it only @@ -22821,6 +23079,7 @@ END @{ @end example @c ENDOFRANGE prunt @c ENDOFRANGE tpul +@c ENDOFRANGE uniq @node Wc Program @subsection Counting Things @@ -22837,6 +23096,7 @@ END @{ @cindex characters, counting @c STARTOFRANGE lico @cindex lines, counting +@c STARTOFRANGE wc @cindex @command{wc} utility The @command{wc} (word count) utility counts lines, words, and characters in one or more input files. Its usage is as follows: @@ -23019,6 +23279,7 @@ END @{ @c ENDOFRANGE lico @c ENDOFRANGE woco @c ENDOFRANGE chco +@c ENDOFRANGE wc @c ENDOFRANGE posimawk @node Miscellaneous Programs @@ -23313,6 +23574,7 @@ seconds are necessary: @c STARTOFRANGE chtra @cindex characters, transliterating +@c STARTOFRANGE tr @cindex @command{tr} utility The system @command{tr} utility transliterates characters. For example, it is often used to map uppercase letters into lowercase for further processing: @@ -23461,6 +23723,7 @@ An obvious improvement to this program would be to set up the assumes that the ``from'' and ``to'' lists will never change throughout the lifetime of the program. @c ENDOFRANGE chtra +@c ENDOFRANGE tr @node Labels Program @subsection Printing Mailing Labels @@ -23520,6 +23783,7 @@ that there are two blank lines at the top and two blank lines at the bottom. The @code{END} rule arranges to flush the final page of labels; there may not have been an even multiple of 20 labels in the data: +@c STARTOFRANGE labels @cindex @code{labels.awk} program @example @c file eg/prog/labels.awk @@ -23587,6 +23851,7 @@ END \ @end example @c ENDOFRANGE prml @c ENDOFRANGE mlprint +@c ENDOFRANGE labels @node Word Sorting @subsection Generating Word-Usage Counts @@ -23653,6 +23918,7 @@ to remove punctuation characters. Finally, we solve the third problem by using the system @command{sort} utility to process the output of the @command{awk} script. Here is the new version of the program: +@c STARTOFRANGE wordfreq @cindex @code{wordfreq.awk} program @example @c file eg/prog/wordfreq.awk @@ -23714,6 +23980,7 @@ have true pipes at the command-line (or batch-file) level. See the general operating system documentation for more information on how to use the @command{sort} program. @c ENDOFRANGE worus +@c ENDOFRANGE wordfreq @node History Sorting @subsection Removing Duplicates from Unsorted Text @@ -23743,6 +24010,7 @@ Each element of @code{lines} is a unique command, and the indices of The @code{END} rule simply prints out the lines, in order: @cindex Rakitzis, Byron +@c STARTOFRANGE histsort @cindex @code{histsort.awk} program @example @c file eg/prog/histsort.awk @@ -23785,6 +24053,7 @@ print data[lines[i]], lines[i] This works because @code{data[$0]} is incremented each time a line is seen. @c ENDOFRANGE lidu +@c ENDOFRANGE histsort @node Extract Program @subsection Extracting Programs from Texinfo Source Files @@ -23895,6 +24164,7 @@ The first rule handles calling @code{system()}, checking that a command is given (@code{NF} is at least three) and also checking that the command exits with a zero exit status, signifying OK: +@c STARTOFRANGE extract @cindex @code{extract.awk} program @example @c file eg/prog/extract.awk @@ -24053,6 +24323,7 @@ END @{ @end example @c ENDOFRANGE texse @c ENDOFRANGE fitex +@c ENDOFRANGE extract @node Simple Sed @subsection A Simple Stream Editor @@ -24082,6 +24353,7 @@ additional arguments are treated as data file names to process. If none are provided, the standard input is used: @cindex Brennan, Michael +@c STARTOFRANGE awksed @cindex @command{awksed.awk} program @c @cindex simple stream editor @c @cindex stream editor, simple @@ -24178,6 +24450,7 @@ Exercise: what are the advantages and disadvantages of this version versus sed? Others? @end ignore +@c ENDOFRANGE awksed @node Igawk Program @subsection An Easy Way to Use Library Functions @@ -24321,6 +24594,7 @@ program. The program is as follows: +@c STARTOFRANGE igawk @cindex @code{igawk.sh} program @example @c file eg/prog/igawk.sh @@ -24493,7 +24767,7 @@ BEGIN @{ @c endfile @end example -The stack is initialized with @code{ARGV[1]}, which will be @file{/dev/stdin}. +The stack is initialized with @code{ARGV[1]}, which will be @samp{/dev/stdin}. The main loop comes next. Input lines are read in succession. Lines that do not start with @samp{@@include} are printed verbatim. If the line does start with @samp{@@include}, the file name is in @code{$2}. @@ -24680,10 +24954,12 @@ statements for the desired library functions. @c ENDOFRANGE libfex @c ENDOFRANGE flibex @c ENDOFRANGE awkpex +@c ENDOFRANGE igawk @node Anagram Program @subsection Finding Anagrams From A Dictionary +@cindex anagrams, finding An interesting programming challenge is to search for @dfn{anagrams} in a word list (such as @@ -24703,6 +24979,7 @@ The following program uses arrays of arrays to bring together words with the same signature and array sorting to print the words in sorted order. +@c STARTOFRANGE anagram @cindex @code{anagram.awk} program @example @c file eg/prog/anagram.awk @@ -24810,10 +25087,13 @@ babels beslab babery yabber @dots{} @end example +@c ENDOFRANGE anagram @node Signature Program @subsection And Now For Something Completely Different +@cindex signature program +@cindex Brini, Davide The following program was written by Davide Brini @c (@email{dave_br@@gmx.com}) and is published on @uref{http://backreference.org/2011/02/03/obfuscated-awk/, @@ -24945,12 +25225,15 @@ It contains the following chapters: @item @ref{Dynamic Extensions}. +@end itemize @end ifdocbook @end ignore @node Advanced Features @chapter Advanced Features of @command{gawk} +@ifset WITH_NETWORK_CHAPTER @cindex advanced features, network connections, See Also networks@comma{} connections +@end ifset @c STARTOFRANGE gawadv @cindex @command{gawk}, features, advanced @c STARTOFRANGE advgaw @@ -25357,9 +25640,9 @@ sorted array traversal is not the default. @subsection Sorting Array Values and Indices with @command{gawk} @cindex arrays, sorting -@cindex @code{asort()} function (@command{gawk}) +@cindexgawkfunc{asort} @cindex @code{asort()} function (@command{gawk}), arrays@comma{} sorting -@cindex @code{asorti()} function (@command{gawk}) +@cindexgawkfunc{asorti} @cindex @code{asorti()} function (@command{gawk}), arrays@comma{} sorting @cindex sort function, arrays, sorting In most @command{awk} implementations, sorting an array requires writing @@ -25454,9 +25737,8 @@ both arrays use the values. @c Document It And Call It A Feature. Sigh. @cindex @command{gawk}, @code{IGNORECASE} variable in -@cindex @code{IGNORECASE} variable -@cindex arrays, sorting, @code{IGNORECASE} variable and -@cindex @code{IGNORECASE} variable, array sorting and +@cindex arrays, sorting, and @code{IGNORECASE} variable +@cindex @code{IGNORECASE} variable, and array sorting functions Because @code{IGNORECASE} affects string comparisons, the value of @code{IGNORECASE} also affects sorting for both @code{asort()} and @code{asorti()}. Note also that the locale's sorting order does @emph{not} @@ -25535,7 +25817,7 @@ open a @emph{two-way} pipe to another process. The second process is termed a @dfn{coprocess}, since it runs in parallel with @command{gawk}. The two-way connection is created using the @samp{|&} operator (borrowed from the Korn shell, @command{ksh}):@footnote{This is very -different from the same operator in the C shell.} +different from the same operator in the C shell and in Bash.} @example do @{ @@ -25625,7 +25907,7 @@ As a side note, the assignment @samp{LC_ALL=C} in the @command{sort} command ensures traditional Unix (ASCII) sorting from @command{sort}. @cindex @command{gawk}, @code{PROCINFO} array in -@cindex @code{PROCINFO} array +@cindex @code{PROCINFO} array, and communications via ptys You may also use pseudo-ttys (ptys) for two-way communication instead of pipes, if your system supports them. This is done on a per-command basis, by setting a special element @@ -25823,52 +26105,60 @@ foo junk @end example -Here is the @file{awkprof.out} that results from running the @command{gawk} -profiler on this program and data (this example also illustrates that @command{awk} -programmers sometimes have to work late): +Here is the @file{awkprof.out} that results from running the +@command{gawk} profiler on this program and data. (This example also +illustrates that @command{awk} programmers sometimes get up very early +in the morning to work.) -@cindex @code{BEGIN} pattern -@cindex @code{END} pattern +@cindex @code{BEGIN} pattern, and profiling +@cindex @code{END} pattern, and profiling @example - # gawk profile, created Sun Aug 13 00:00:15 2000 + # gawk profile, created Thu Feb 27 05:16:21 2014 - # BEGIN block(s) + # BEGIN block(s) - BEGIN @{ - 1 print "First BEGIN rule" - 1 print "Second BEGIN rule" - @} + BEGIN @{ + 1 print "First BEGIN rule" + @} - # Rule(s) + BEGIN @{ + 1 print "Second BEGIN rule" + @} - 5 /foo/ @{ # 2 - 2 print "matched /foo/, gosh" - 6 for (i = 1; i <= 3; i++) @{ - 6 sing() - @} - @} + # Rule(s) - 5 @{ - 5 if (/foo/) @{ # 2 - 2 print "if is true" - 3 @} else @{ - 3 print "else is true" - @} - @} + 5 /foo/ @{ # 2 + 2 print "matched /foo/, gosh" + 6 for (i = 1; i <= 3; i++) @{ + 6 sing() + @} + @} - # END block(s) + 5 @{ + 5 if (/foo/) @{ # 2 + 2 print "if is true" + 3 @} else @{ + 3 print "else is true" + @} + @} - END @{ - 1 print "First END rule" - 1 print "Second END rule" - @} + # END block(s) - # Functions, listed alphabetically + END @{ + 1 print "First END rule" + @} - 6 function sing(dummy) - @{ - 6 print "I gotta be me!" - @} + END @{ + 1 print "Second END rule" + @} + + + # Functions, listed alphabetically + + 6 function sing(dummy) + @{ + 6 print "I gotta be me!" + @} @end example This example illustrates many of the basic features of profiling output. @@ -25876,15 +26166,16 @@ They are as follows: @itemize @bullet @item -The program is printed in the order @code{BEGIN} rule, -@code{BEGINFILE} rule, +The program is printed in the order @code{BEGIN} rules, +@code{BEGINFILE} rules, pattern/action rules, -@code{ENDFILE} rule, @code{END} rule and functions, listed +@code{ENDFILE} rules, @code{END} rules and functions, listed alphabetically. -Multiple @code{BEGIN} and @code{END} rules are merged together, -as are multiple @code{BEGINFILE} and @code{ENDFILE} rules. +Multiple @code{BEGIN} and @code{END} rules retain their +separate identities, as do +multiple @code{BEGINFILE} and @code{ENDFILE} rules. -@cindex patterns, counts +@cindex patterns, counts, in a profile @item Pattern-action rules have two counts. The first count, to the left of the rule, shows how many times @@ -25904,7 +26195,7 @@ is a count showing how many times the condition was true. The count for the @code{else} indicates how many times the test failed. -@cindex loops, count for header +@cindex loops, count for header, in a profile @item The count for a loop header (such as @code{for} or @code{while}) shows how many times the loop test was executed. @@ -25912,8 +26203,8 @@ or @code{while}) shows how many times the loop test was executed. statement in a rule to determine how many times the rule was executed. If the first statement is a loop, the count is misleading.) -@cindex functions, user-defined, counts -@cindex user-defined, functions, counts +@cindex functions, user-defined, counts, in a profile +@cindex user-defined, functions, counts, in a profile @item For user-defined functions, the count next to the @code{function} keyword indicates how many times the function was called. @@ -25927,8 +26218,8 @@ The layout uses ``K&R'' style with TABs. Braces are used everywhere, even when the body of an @code{if}, @code{else}, or loop is only a single statement. -@cindex @code{()} (parentheses) -@cindex parentheses @code{()} +@cindex @code{()} (parentheses), in a profile +@cindex parentheses @code{()}, in a profile @item Parentheses are used only where needed, as indicated by the structure of the program and the precedence rules. @@ -25963,8 +26254,8 @@ typed when you wrote it. This is because @command{gawk} creates the profiled version by ``pretty printing'' its internal representation of the program. The advantage to this is that @command{gawk} can produce a standard representation. The disadvantage is that all source-code -comments are lost, as are the distinctions among multiple @code{BEGIN}, -@code{END}, @code{BEGINFILE}, and @code{ENDFILE} rules. Also, things such as: +comments are lost. +Also, things such as: @example /foo/ @@ -25984,6 +26275,7 @@ which is correct, but possibly surprising. @cindex profiling @command{awk} programs, dynamically @cindex @command{gawk} program, dynamic profiling +@cindex dynamic profiling Besides creating profiles when a program has completed, @command{gawk} can produce a profile while it is running. This is useful if your @command{awk} program goes into an @@ -25997,9 +26289,9 @@ $ @kbd{gawk --profile -f myprog &} @end example @cindex @command{kill} command@comma{} dynamic profiling -@cindex @code{USR1} signal -@cindex @code{SIGUSR1} signal -@cindex signals, @code{USR1}/@code{SIGUSR1} +@cindex @code{USR1} signal, for dynamic profiling +@cindex @code{SIGUSR1} signal, for dynamic profiling +@cindex signals, @code{USR1}/@code{SIGUSR1}, for profiling @noindent The shell prints a job number and process ID number; in this case, 13992. Use the @command{kill} command to send the @code{USR1} signal @@ -26030,9 +26322,9 @@ You may send @command{gawk} the @code{USR1} signal as many times as you like. Each time, the profile and function call trace are appended to the output profile file. -@cindex @code{HUP} signal -@cindex @code{SIGHUP} signal -@cindex signals, @code{HUP}/@code{SIGHUP} +@cindex @code{HUP} signal, for dynamic profiling +@cindex @code{SIGHUP} signal, for dynamic profiling +@cindex signals, @code{HUP}/@code{SIGHUP}, for profiling If you use the @code{HUP} signal instead of the @code{USR1} signal, @command{gawk} produces the profile and the function call trace and then exits. @@ -26054,6 +26346,11 @@ keyboard. The @code{INT} signal is generated by the Finally, @command{gawk} also accepts another option, @option{--pretty-print}. When called this way, @command{gawk} ``pretty prints'' the program into @file{awkprof.out}, without any execution counts. + +@quotation NOTE +The @option{--pretty-print} option still runs your program. +This will change in the next major release. +@end quotation @c ENDOFRANGE advgaw @c ENDOFRANGE gawadv @c ENDOFRANGE awkp @@ -26165,6 +26462,7 @@ lookup of the translations. @cindex @code{.po} files @cindex files, @code{.po} +@c STARTOFRANGE portobfi @cindex portable object files @cindex files, portable object @item @@ -26176,6 +26474,7 @@ For example, there might be a @file{fr.po} for a French translation. @cindex @code{.gmo} files @cindex files, @code{.gmo} @cindex message object files +@c STARTOFRANGE portmsgfi @cindex files, message object @item Each language's @file{.po} file is converted into a binary @@ -26323,7 +26622,7 @@ String constants marked with a leading underscore are candidates for translation at runtime. String constants without a leading underscore are not translated. -@cindex @code{dcgettext()} function (@command{gawk}) +@cindexgawkfunc{dcgettext} @item dcgettext(@var{string} @r{[}, @var{domain} @r{[}, @var{category}@r{]]}) Return the translation of @var{string} in text domain @var{domain} for locale category @var{category}. @@ -26349,7 +26648,7 @@ chosen to be simple and to allow for reasonable @command{awk}-style default arguments. @end quotation -@cindex @code{dcngettext()} function (@command{gawk}) +@cindexgawkfunc{dcngettext} @item dcngettext(@var{string1}, @var{string2}, @var{number} @r{[}, @var{domain} @r{[}, @var{category}@r{]]}) Return the plural form used for @var{number} of the translation of @var{string1} and @var{string2} in text domain @@ -26365,7 +26664,7 @@ The same remarks about argument order as for the @code{dcgettext()} function app @cindex files, @code{.gmo}, specifying directory of @cindex message object files, specifying directory of @cindex files, message object, specifying directory of -@cindex @code{bindtextdomain()} function (@command{gawk}) +@cindexgawkfunc{bindtextdomain} @item bindtextdomain(@var{directory} @r{[}, @var{domain}@r{]}) Change the directory in which @code{gettext} looks for @file{.gmo} files, in case they @@ -26467,7 +26766,7 @@ and use translations from @command{awk}. @cindex portable object files @cindex files, portable object Once a program's translatable strings have been marked, they must -be extracted to create the initial @file{.po} file. +be extracted to create the initial @file{.pot} file. As part of translation, it is often helpful to rearrange the order in which arguments to @code{printf} are output. @@ -26516,6 +26815,8 @@ second argument to @code{dcngettext()}.@footnote{The @xref{I18N Example}, for the full list of steps to go through to create and test translations for @command{guide}. +@c ENDOFRANGE portobfi +@c ENDOFRANGE portmsgfi @node Printf Ordering @subsection Rearranging @code{printf} Arguments @@ -26562,7 +26863,7 @@ example, @samp{string} is the first argument and @samp{length(string)} is the se @example $ @kbd{gawk 'BEGIN @{} > @kbd{string = "Dont Panic"} -> @kbd{printf _"%2$d characters live in \"%1$s\"\n",} +> @kbd{printf "%2$d characters live in \"%1$s\"\n",} > @kbd{string, length(string)} > @kbd{@}'} @print{} 10 characters live in "Dont Panic" @@ -26596,7 +26897,7 @@ This is somewhat counterintuitive. and those with positional specifiers in the same string: @example -$ @kbd{gawk 'BEGIN @{ printf _"%d %3$s\n", 1, 2, "hi" @}'} +$ @kbd{gawk 'BEGIN @{ printf "%d %3$s\n", 1, 2, "hi" @}'} @error{} gawk: cmd. line:1: fatal: must use `count$' on all formats or none @end example @@ -26937,6 +27238,7 @@ The following list defines terms used throughout the rest of this @value{CHAPTER}. @table @dfn +@cindex stack frame @item Stack Frame Programs generally call functions during the course of their execution. One function can call another, or a function can call itself (recursion). @@ -26958,6 +27260,7 @@ invoked. Commands that print the call stack print information about each stack frame (as detailed later on). @item Breakpoint +@cindex breakpoint During debugging, you often wish to let the program run until it reaches a certain point, and then continue execution from there one statement (or instruction) at a time. The way to do this is to set @@ -26967,6 +27270,7 @@ take over control of the program's execution. You can add and remove as many breakpoints as you like. @item Watchpoint +@cindex watchpoint A watchpoint is similar to a breakpoint. The difference is that breakpoints are oriented around the code: stop when a certain point in the code is reached. A watchpoint, however, specifies that program execution @@ -26998,6 +27302,7 @@ by the higher-level @command{awk} commands. @node Sample Debugging Session @section Sample Debugging Session +@cindex sample debugging session In order to illustrate the use of @command{gawk} as a debugger, let's look at a sample debugging session. We will use the @command{awk} implementation of the @@ -27011,13 +27316,16 @@ as our example. @node Debugger Invocation @subsection How to Start the Debugger +@cindex starting the debugger +@cindex debugger, how to start -Starting the debugger is almost exactly like running @command{awk}, except you have to -pass an additional option @option{--debug} or the corresponding short option @option{-D}. -The file(s) containing the program and any supporting code are given on the command -line as arguments to one or more @option{-f} options. (@command{gawk} is not designed -to debug command-line programs, only programs contained in files.) In our case, -we invoke the debugger like this: +Starting the debugger is almost exactly like running @command{gawk}, +except you have to pass an additional option @option{--debug} or the +corresponding short option @option{-D}. The file(s) containing the +program and any supporting code are given on the command line as arguments +to one or more @option{-f} options. (@command{gawk} is not designed +to debug command-line programs, only programs contained in files.) +In our case, we invoke the debugger like this: @example $ @kbd{gawk -D -f getopt.awk -f join.awk -f uniq.awk inputfile} @@ -27150,7 +27458,7 @@ gawk> @kbd{p NR} @noindent So we can see that @code{are_equal()} was only called for the second record -of the file. Of course, this is because our program contained a rule for +of the file. Of course, this is because our program contains a rule for @samp{NR == 1}: @example @@ -27350,21 +27658,24 @@ controlling breakpoints are: @cindex debugger commands, @code{break} @cindex @code{break} debugger command @cindex @code{b} debugger command (alias for @code{break}) +@cindex set breakpoint +@cindex breakpoint, setting @item @code{break} [[@var{filename}@code{:}]@var{n} | @var{function}] [@code{"@var{expression}"}] @itemx @code{b} [[@var{filename}@code{:}]@var{n} | @var{function}] [@code{"@var{expression}"}] Without any argument, set a breakpoint at the next instruction to be executed in the selected stack frame. Arguments can be one of the following: +@c @asis for docbook @c nested table -@table @var -@item n +@table @asis +@item @var{n} Set a breakpoint at line number @var{n} in the current source file. -@item filename@code{:}n +@item @var{filename}@code{:}@var{n} Set a breakpoint at line number @var{n} in source file @var{filename}. -@item function +@item @var{function} Set a breakpoint at entry to (the first instruction of) function @var{function}. @end table @@ -27380,6 +27691,8 @@ it continues executing the program. @cindex debugger commands, @code{clear} @cindex @code{clear} debugger command +@cindex delete breakpoint at location +@cindex breakpoint at location, how to delete @item @code{clear} [[@var{filename}@code{:}]@var{n} | @var{function}] Without any argument, delete any breakpoint at the next instruction to be executed in the selected stack frame. If the program stops at @@ -27387,19 +27700,20 @@ a breakpoint, this deletes that breakpoint so that the program does not stop at that location again. Arguments can be one of the following: @c nested table -@table @var -@item n +@table @asis +@item @var{n} Delete breakpoint(s) set at line number @var{n} in the current source file. -@item filename@code{:}n +@item @var{filename}@code{:}@var{n} Delete breakpoint(s) set at line number @var{n} in source file @var{filename}. -@item function +@item @var{function} Delete breakpoint(s) set at entry to function @var{function}. @end table @cindex debugger commands, @code{condition} @cindex @code{condition} debugger command +@cindex breakpoint condition @item @code{condition} @var{n} @code{"@var{expression}"} Add a condition to existing breakpoint or watchpoint @var{n}. The condition is an @command{awk} expression that the debugger evaluates @@ -27413,6 +27727,8 @@ watchpoint is made unconditional. @cindex debugger commands, @code{delete} @cindex @code{delete} debugger command @cindex @code{d} debugger command (alias for @code{delete}) +@cindex delete breakpoint by number +@cindex breakpoint, delete by number @item @code{delete} [@var{n1 n2} @dots{}] [@var{n}--@var{m}] @itemx @code{d} [@var{n1 n2} @dots{}] [@var{n}--@var{m}] Delete specified breakpoints or a range of breakpoints. Deletes @@ -27420,6 +27736,8 @@ all defined breakpoints if no argument is supplied. @cindex debugger commands, @code{disable} @cindex @code{disable} debugger command +@cindex disable breakpoint +@cindex breakpoint, how to disable or enable @item @code{disable} [@var{n1 n2} @dots{} | @var{n}--@var{m}] Disable specified breakpoints or a range of breakpoints. Without any argument, disables all breakpoints. @@ -27428,6 +27746,7 @@ any argument, disables all breakpoints. @cindex debugger commands, @code{enable} @cindex @code{enable} debugger command @cindex @code{e} debugger command (alias for @code{enable}) +@cindex enable breakpoint @item @code{enable} [@code{del} | @code{once}] [@var{n1 n2} @dots{}] [@var{n}--@var{m}] @itemx @code{e} [@code{del} | @code{once}] [@var{n1 n2} @dots{}] [@var{n}--@var{m}] Enable specified breakpoints or a range of breakpoints. Without @@ -27447,6 +27766,7 @@ the program stops at the breakpoint. @cindex debugger commands, @code{ignore} @cindex @code{ignore} debugger command +@cindex ignore breakpoint @item @code{ignore} @var{n} @var{count} Ignore breakpoint number @var{n} the next @var{count} times it is hit. @@ -27455,6 +27775,7 @@ hit. @cindex debugger commands, @code{tbreak} @cindex @code{tbreak} debugger command @cindex @code{t} debugger command (alias for @code{tbreak}) +@cindex temporary breakpoint @item @code{tbreak} [[@var{filename}@code{:}]@var{n} | @var{function}] @itemx @code{t} [[@var{filename}@code{:}]@var{n} | @var{function}] Set a temporary breakpoint (enabled for only one stop). @@ -27475,6 +27796,8 @@ execution of the program than we saw in our earlier example: @cindex @code{silent} debugger command @cindex debugger commands, @code{end} @cindex @code{end} debugger command +@cindex breakpoint commands +@cindex commands to execute at breakpoint @item @code{commands} [@var{n}] @itemx @code{silent} @itemx @dots{} @@ -27502,6 +27825,7 @@ gawk> @cindex debugger commands, @code{c} (@code{continue}) @cindex debugger commands, @code{continue} +@cindex continue program, in debugger @item @code{continue} [@var{count}] @itemx @code{c} [@var{count}] Resume program execution. If continued from a breakpoint and @var{count} is @@ -27518,6 +27842,7 @@ Print the returned value. @cindex debugger commands, @code{next} @cindex @code{next} debugger command @cindex @code{n} debugger command (alias for @code{next}) +@cindex single-step execution, in the debugger @item @code{next} [@var{count}] @itemx @code{n} [@var{count}] Continue execution to the next source line, stepping over function calls. @@ -27612,6 +27937,7 @@ items on the list. @cindex debugger commands, @code{eval} @cindex @code{eval} debugger command +@cindex evaluate expressions, in debugger @item @code{eval "@var{awk statements}"} Evaluate @var{awk statements} in the context of the running program. You can do anything that an @command{awk} program would do: assign @@ -27629,6 +27955,7 @@ parameters defined by the program. @cindex debugger commands, @code{print} @cindex @code{print} debugger command @cindex @code{p} debugger command (alias for @code{print}) +@cindex print variables, in debugger @item @code{print} @var{var1}[@code{,} @var{var2} @dots{}] @itemx @code{p} @var{var1}[@code{,} @var{var2} @dots{}] Print the value of a @command{gawk} variable or field. @@ -27662,6 +27989,7 @@ No newline is printed unless one is specified. @cindex debugger commands, @code{set} @cindex @code{set} debugger command +@cindex assign values to variables, in debugger @item @code{set} @var{var}@code{=}@var{value} Assign a constant (number or string) value to an @command{awk} variable or field. @@ -27674,6 +28002,7 @@ You can also set special @command{awk} variables, such as @code{FS}, @cindex debugger commands, @code{watch} @cindex @code{watch} debugger command @cindex @code{w} debugger command (alias for @code{watch}) +@cindex set watchpoint @item @code{watch} @var{var} | @code{$}@var{n} [@code{"@var{expression}"}] @itemx @code{w} @var{var} | @code{$}@var{n} [@code{"@var{expression}"}] Add variable @var{var} (or field @code{$@var{n}}) to the watch list. @@ -27690,12 +28019,14 @@ then the debugger stops execution and prompts for a command. Otherwise, @cindex debugger commands, @code{undisplay} @cindex @code{undisplay} debugger command +@cindex stop automatic display, in debugger @item @code{undisplay} [@var{n}] Remove item number @var{n} (or all items, if no argument) from the automatic display list. @cindex debugger commands, @code{unwatch} @cindex @code{unwatch} debugger command +@cindex delete watchpoint @item @code{unwatch} [@var{n}] Remove item number @var{n} (or all items, if no argument) from the watch list. @@ -27716,6 +28047,8 @@ functions which called the one you are in. The commands for doing this are: @cindex debugger commands, @code{backtrace} @cindex @code{backtrace} debugger command @cindex @code{bt} debugger command (alias for @code{backtrace}) +@cindex call stack, display in debugger +@cindex traceback, display in debugger @item @code{backtrace} [@var{count}] @itemx @code{bt} [@var{count}] Print a backtrace of all function calls (stack frames), or innermost @var{count} @@ -27769,25 +28102,32 @@ The value for @var{what} should be one of the following: @c nested table @table @code @item args +@cindex show function arguments, in debugger Arguments of the selected frame. @item break +@cindex show breakpoints List all currently set breakpoints. @item display +@cindex automatic displays, in debugger List all items in the automatic display list. @item frame +@cindex describe call stack frame, in debugger Description of the selected stack frame. @item functions +@cindex list function definitions, in debugger List all function definitions including source file names and line numbers. @item locals +@cindex show local variables, in debugger Local variables of the selected frame. @item source +@cindex show name of current source file, in debugger The name of the current source file. Each time the program stops, the current source file is the file containing the current instruction. When the debugger first starts, the current source file is the first file @@ -27796,12 +28136,15 @@ included via the @option{-f} option. The be used at any time to change the current source. @item sources +@cindex show all source files, in debugger List all program sources. @item variables +@cindex list all global variables, in debugger List all global variables. @item watch +@cindex show watchpoints List all items in the watch list. @end table @end table @@ -27815,6 +28158,8 @@ from a file. The commands are: @cindex debugger commands, @code{option} @cindex @code{option} debugger command @cindex @code{o} debugger command (alias for @code{option}) +@cindex display debugger options +@cindex debugger options @item @code{option} [@var{name}[@code{=}@var{value}]] @itemx @code{o} [@var{name}[@code{=}@var{value}]] Without an argument, display the available debugger options @@ -27826,30 +28171,37 @@ The available options are: @c nested table @table @code @item history_size +@cindex debugger history size The maximum number of lines to keep in the history file @file{./.gawk_history}. The default is 100. @item listsize +@cindex debugger default list amount The number of lines that @code{list} prints. The default is 15. @item outfile +@cindex redirect @command{gawk} output, in debugger Send @command{gawk} output to a file; debugger output still goes to standard output. An empty string (@code{""}) resets output to standard output. @item prompt +@cindex debugger prompt The debugger prompt. The default is @samp{@w{gawk> }}. @item save_history @r{[}on @r{|} off@r{]} +@cindex debugger history file Save command history to file @file{./.gawk_history}. The default is @code{on}. @item save_options @r{[}on @r{|} off@r{]} +@cindex save debugger options Save current options to file @file{./.gawkrc} upon exit. The default is @code{on}. Options are read back in to the next session upon startup. @item trace @r{[}on @r{|} off@r{]} +@cindex instruction tracing, in debugger Turn instruction tracing on or off. The default is @code{off}. @end table @@ -27858,6 +28210,7 @@ Save the commands from the current session to the given file name, so that they can be replayed using the @command{source} command. @item @code{source} @var{filename} +@cindex debugger, read commands from a file Run command(s) from a file; an error in any command does not terminate execution of subsequent commands. Comments (lines starting with @samp{#}) are allowed in a command file. @@ -27956,8 +28309,8 @@ about the command @var{command}. @cindex debugger commands, @code{list} @cindex @code{list} debugger command @cindex @code{l} debugger command (alias for @code{list}) -@item @code{list} [@code{-} | @code{+} | @var{n} | @var{filename@code{:}n} | @var{n}--@var{m} | @var{function}] -@itemx @code{l} [@code{-} | @code{+} | @var{n} | @var{filename@code{:}n} | @var{n}--@var{m} | @var{function}] +@item @code{list} [@code{-} | @code{+} | @var{n} | @var{filename}@code{:}@var{n} | @var{n}--@var{m} | @var{function}] +@itemx @code{l} [@code{-} | @code{+} | @var{n} | @var{filename}@code{:}@var{n} | @var{n}--@var{m} | @var{function}] Print the specified lines (default 15) from the current source file or the file named @var{filename}. The possible arguments to @code{list} are as follows: @@ -27977,7 +28330,7 @@ Print lines centered around line number @var{n}. @item @var{n}--@var{m} Print lines from @var{n} to @var{m}. -@item @var{filename@code{:}n} +@item @var{filename}@code{:}@var{n} Print lines centered around line number @var{n} in source file @var{filename}. This command may change the current source file. @@ -27990,6 +28343,7 @@ function @var{function}. This command may change the current source file. @cindex debugger commands, @code{quit} @cindex @code{quit} debugger command @cindex @code{q} debugger command (alias for @code{quit}) +@cindex exit the debugger @item @code{quit} @itemx @code{q} Exit the debugger. Debugging is great fun, but sometimes we all have @@ -28013,6 +28367,8 @@ fairly self-explanatory, and using @code{stepi} and @code{nexti} while @node Readline Support @section Readline Support +@cindex command completion, in debugger +@cindex history expansion, in debugger If @command{gawk} is compiled with the @code{readline} library, you can take advantage of that library's command completion and history expansion @@ -28100,9 +28456,7 @@ be added, and of course feel free to try to add them yourself! @cindex arbitrary precision @cindex multiple precision @cindex infinite precision -@cindex floating-point numbers, arbitrary precision -@cindex MPFR -@cindex GMP +@cindex floating-point, numbers@comma{} arbitrary precision @cindex Knuth, Donald @quotation @@ -28446,23 +28800,38 @@ then the answer is @math{2^{53}}. @end iftex @ifnottex +@ifnotdocbook 2^53. +@end ifnotdocbook @end ifnottex +@docbook +2<superscript>53</superscript>. @c +@end docbook The next representable number is the even number @iftex @math{2^{53} + 2}, @end iftex @ifnottex +@ifnotdocbook 2^53 + 2, +@end ifnotdocbook @end ifnottex +@docbook +2<superscript>53</superscript> + 2, @c +@end docbook meaning it is unlikely that you will be able to make @command{gawk} print @iftex @math{2^{53} + 1} @end iftex @ifnottex +@ifnotdocbook 2^53 + 1 +@end ifnotdocbook @end ifnottex +@docbook +2<superscript>53</superscript> + 1 @c +@end docbook in integer format. The range of integers exactly representable by a 64-bit double is @@ -28470,8 +28839,13 @@ is @math{[-2^{53}, 2^{53}]}. @end iftex @ifnottex +@ifnotdocbook [@minus{}2^53, 2^53]. +@end ifnotdocbook @end ifnottex +@docbook +[−2<superscript>53</superscript>, 2<superscript>53</superscript>]. @c +@end docbook If you ever see an integer outside this range in @command{awk} using 64-bit doubles, you have reason to be very suspicious about the accuracy of the output. Here is a simple program with erroneous output: @@ -28695,8 +29069,13 @@ number is then @math{s @cdot 2^e}. @end iftex @ifnottex +@ifnotdocbook @var{s * 2^e}. +@end ifnotdocbook @end ifnottex +@docbook +<emphasis>s ⋅ 2<superscript>e</superscript></emphasis>. @c +@end docbook The first bit of a non-zero binary significand is always one, so the significand in an IEEE-754 format only includes the fractional part, leaving the leading one implicit. @@ -28866,6 +29245,8 @@ when you change the rounding mode. @node Gawk and MPFR @section @command{gawk} + MPFR = Powerful Arithmetic +@cindex MPFR +@cindex GMP The rest of this @value{CHAPTER} describes how to use the arbitrary precision (also known as @dfn{multiple precision} or @dfn{infinite precision}) numeric @@ -28878,12 +29259,17 @@ The easiest way to find out is to look at the output of the following command: @example -$ @kbd{gawk --version} -@print{} GNU Awk 4.1.0, API: 1.0 (GNU MPFR 3.1.0-p3, GNU MP 5.0.2) -@print{} Copyright (C) 1989, 1991-2013 Free Software Foundation. +$ @kbd{./gawk --version} +@print{} GNU Awk 4.1.1, API: 1.1 (GNU MPFR 3.1.0-p3, GNU MP 5.0.2) +@print{} Copyright (C) 1989, 1991-2014 Free Software Foundation. @dots{} @end example +@noindent +(You may see different version numbers than what's shown here. That's OK; +what's important is to see that GNU MPFR and GNU MP are listed in +the output.) + @command{gawk} uses the @uref{http://www.mpfr.org, GNU MPFR} and @@ -28937,8 +29323,13 @@ numbers are not implemented.} (@math{emax = 2^{30} - 1, emin = -emax}) @end iftex @ifnottex +@ifnotdocbook (@var{emax} = 2^30 @minus{} 1, @var{emin} = @minus{}@var{emax}) +@end ifnotdocbook @end ifnottex +@docbook +(<emphasis>emax</emphasis> = 2<superscript>30</superscript> − 1, <emphasis>emin</emphasis> = −<emphasis>emax</emphasis>) @c +@end docbook for all floating-point contexts. There is no explicit mechanism to adjust the exponent range. MPFR does not implement subnormal numbers by default, @@ -28970,6 +29361,7 @@ your program. @node Setting Precision @subsection Setting the Working Precision @cindex @code{PREC} variable +@cindex setting working precision @command{gawk} uses a global working precision; it does not keep track of the precision or accuracy of individual numbers. Performing an arithmetic @@ -29009,8 +29401,15 @@ formula: @math{prec = 3.322 @cdot dps} @end iftex @ifnottex +@ifnotdocbook @var{prec} = 3.322 * @var{dps} +@end ifnotdocbook @end ifnottex +@docbook +<para> +<emphasis>prec</emphasis> = 3.322 ⋅ <emphasis>dps</emphasis> @c +</para> +@end docbook @noindent Here, @var{prec} denotes the binary precision @@ -29045,6 +29444,7 @@ issues that occur because numbers are stored internally in binary. @node Setting Rounding Mode @subsection Setting the Rounding Mode @cindex @code{ROUNDMODE} variable +@cindex setting rounding mode The @code{ROUNDMODE} variable provides program level control over the rounding mode. @@ -29112,6 +29512,7 @@ In the first case, the number is stored with the default precision of 53 bits. @node Changing Precision @subsection Changing the Precision of a Number +@cindex changing precision of a number @cindex Laurie, Dirk @quotation @@ -29229,7 +29630,8 @@ the problem at hand is often the correct approach in such situations. @node Arbitrary Precision Integers @section Arbitrary Precision Integer Arithmetic with @command{gawk} -@cindex integer, arbitrary precision +@cindex integers, arbitrary precision +@cindex arbitrary precision integers If one of the options @option{--bignum} or @option{-M} is specified, @command{gawk} performs all @@ -29243,8 +29645,13 @@ For example, the following computes @math{5^{4^{3^{2}}}}, @end iftex @ifnottex +@ifnotdocbook 5^4^3^2, +@end ifnotdocbook @end ifnottex +@docbook +5<superscript>4<superscript>3<superscript>2</superscript></superscript></superscript>, @c +@end docbook the result of which is beyond the limits of ordinary @command{gawk} numbers: @@ -29266,9 +29673,16 @@ floating-point values instead, the precision needed for correct output would be @math{3.322 @cdot 183231}, @end iftex @ifnottex +@ifnotdocbook @samp{prec = 3.322 * dps}), would be 3.322 x 183231, +@end ifnotdocbook @end ifnottex +@docbook +<emphasis>prec</emphasis> = 3.322 ⋅ <emphasis>dps</emphasis>), +would be +<emphasis>prec</emphasis> = 3.322 ⋅ 183231, @c +@end docbook or 608693. The result from an arithmetic operation with an integer and a floating-point value @@ -29317,7 +29731,7 @@ to begin with: gawk -M 'BEGIN @{ n = 13.0; print n % 2.0 @}' @end example -Note that for the particular example above, there is likely best +Note that for the particular example above, it is likely best to just use the following: @example @@ -29326,6 +29740,7 @@ gawk -M 'BEGIN @{ n = 13; print n % 2 @}' @node Dynamic Extensions @chapter Writing Extensions for @command{gawk} +@cindex dynamically loaded extensions It is possible to add new functions written in C or C++ to @command{gawk} using dynamically loaded libraries. This facility is available on systems @@ -29360,6 +29775,7 @@ When @option{--sandbox} is specified, extensions are disabled @node Extension Intro @section Introduction +@cindex plug-in An @dfn{extension} (sometimes called a @dfn{plug-in}) is a piece of external compiled code that @command{gawk} can load at runtime to provide additional functionality, over and above the built-in capabilities @@ -29405,8 +29821,14 @@ Communication between @command{gawk} and an extension is two-way. First, when an extension is loaded, it is passed a pointer to a @code{struct} whose fields are function pointers. +@ifnotdocbook This is shown in @ref{load-extension}. +@end ifnotdocbook +@ifdocbook +This is shown in @inlineraw{docbook, <xref linkend="load-extension"/>}. +@end ifdocbook +@ifnotdocbook @float Figure,load-extension @caption{Loading The Extension} @c FIXME: One day, it should not be necessary to have two cases, @@ -29419,13 +29841,27 @@ This is shown in @ref{load-extension}. @center @image{api-figure1, , , Loading the extension} @end ifnotinfo @end float +@end ifnotdocbook + +@docbook +<figure id="load-extension"> +<title>Loading the extension</title> +<graphic fileref="api-figure1.eps"/> +</figure> +@end docbook The extension can call functions inside @command{gawk} through these function pointers, at runtime, without needing (link-time) access to @command{gawk}'s symbols. One of these function pointers is to a function for ``registering'' new built-in functions. +@ifnotdocbook This is shown in @ref{load-new-function}. +@end ifnotdocbook +@ifdocbook +This is shown in @inlineraw{docbook, <xref linkend="load-new-function"/>}. +@end ifdocbook +@ifnotdocbook @float Figure,load-new-function @caption{Loading The New Function} @ifinfo @@ -29435,14 +29871,28 @@ This is shown in @ref{load-new-function}. @center @image{api-figure2, , , Loading the new function} @end ifnotinfo @end float +@end ifnotdocbook + +@docbook +<figure id="load-new-function"> +<title>Loading the new function</title> +<graphic fileref="api-figure2.eps"/> +</figure> +@end docbook In the other direction, the extension registers its new functions with @command{gawk} by passing function pointers to the functions that provide the new feature (@code{do_chdir()}, for example). @command{gawk} associates the function pointer with a name and can then call it, using a defined calling convention. +@ifnotdocbook This is shown in @ref{call-new-function}. +@end ifnotdocbook +@ifdocbook +This is shown in @inlineraw{docbook, <xref linkend="call-new-function"/>}. +@end ifdocbook +@ifnotdocbook @float Figure,call-new-function @caption{Calling The New Function} @ifinfo @@ -29452,6 +29902,14 @@ This is shown in @ref{call-new-function}. @center @image{api-figure3, , , Calling the new function} @end ifnotinfo @end float +@end ifnotdocbook + +@docbook +<figure id="call-new-function"> +<title>Calling The New Function</title> +<graphic fileref="api-figure3.eps"/> +</figure> +@end docbook The @code{do_@var{xxx}()} function, in turn, then uses the function pointers in the API @code{struct} to do its work, such as updating @@ -29488,6 +29946,7 @@ happen, but we all know how @emph{that} goes.) @node Extension API Description @section API Description +@cindex extension API This (rather large) @value{SECTION} describes the API in detail. @@ -29495,6 +29954,7 @@ This (rather large) @value{SECTION} describes the API in detail. * Extension API Functions Introduction:: Introduction to the API functions. * General Data Types:: The data types. * Requesting Values:: How to get a value. +* Memory Allocation Functions:: Functions for allocating memory. * Constructor Functions:: Functions for creating values. * Registration Functions:: Functions to register things with @command{gawk}. @@ -29550,6 +30010,9 @@ Symbol table access: retrieving a global variable, creating one, or changing one. @item +Allocating, reallocating, and releasing memory. + +@item Creating and releasing cached values; this provides an efficient way to use values for multiple variables and can be a big performance win. @@ -29588,10 +30051,8 @@ corresponding standard header file @emph{before} including @file{gawkapi.h}: @item @code{EOF} @tab @code{<stdio.h>} @item @code{FILE} @tab @code{<stdio.h>} @item @code{NULL} @tab @code{<stddef.h>} -@item @code{malloc()} @tab @code{<stdlib.h>} @item @code{memcpy()} @tab @code{<string.h>} @item @code{memset()} @tab @code{<string.h>} -@item @code{realloc()} @tab @code{<stdlib.h>} @item @code{size_t} @tab @code{<sys/types.h>} @item @code{struct stat} @tab @code{<sys/stat.h>} @end multitable @@ -29621,8 +30082,9 @@ does not support this keyword, you should either place All pointers filled in by @command{gawk} are to memory managed by @command{gawk} and should be treated by the extension as read-only. Memory for @emph{all} strings passed into @command{gawk} -from the extension @emph{must} come from @code{malloc()} and is managed -by @command{gawk} from then on. +from the extension @emph{must} come from calling the API-provided function +pointers @code{api_malloc()}, @code{api_calloc()} or @code{api_realloc()}, +and is managed by @command{gawk} from then on. @item The API defines several simple @code{struct}s that map values as seen @@ -29662,6 +30124,8 @@ the macros as if they were functions. @node General Data Types @subsection General Purpose Data Types +@cindex Robbins, Arnold +@cindex Ramey, Chet @quotation @i{I have a true love/hate relationship with unions.} @author Arnold Robbins @@ -29702,7 +30166,8 @@ A simple boolean type. This represents a mutable string. @command{gawk} owns the memory pointed to if it supplied the value. Otherwise, it takes ownership of the memory pointed to. -@strong{Such memory must come from @code{malloc()}!} +@strong{Such memory must come from calling the API-provided function +pointers @code{api_malloc()}, @code{api_calloc()}, or @code{api_realloc()}!} As mentioned earlier, strings are maintained using the current multibyte encoding. @@ -29818,7 +30283,94 @@ print an error message, or reissue the request for the actual value type, as appropriate. This behavior is summarized in @ref{table-value-types-returned}. +@c FIXME: Try to do this with spans... +@ifdocbook +@anchor{table-value-types-returned} +@end ifdocbook +@docbook +<informaltable> +<tgroup cols="2"> + <colspec colwidth="50*"/><colspec colwidth="50*"/> + <thead> + <row><entry></entry><entry><para>Type of Actual Value:</para></entry></row> + </thead> + <tbody> + <row><entry></entry><entry></entry></row> + </tbody> +</tgroup> +<tgroup cols="6"> + <colspec colwidth="16.6*"/> + <colspec colwidth="16.6*"/> + <colspec colwidth="19.8*"/> + <colspec colwidth="15*"/> + <colspec colwidth="15*"/> + <colspec colwidth="16.6*"/> + <thead> + <row> + <entry></entry> + <entry></entry> + <entry><para>String</para></entry> + <entry><para>Number</para></entry> + <entry><para>Array</para></entry> + <entry><para>Undefined</para></entry> + </row> + </thead> + <tbody> + <row> + <entry></entry> + <entry><para><emphasis role="bold">String</emphasis></para></entry> + <entry><para>String</para></entry> + <entry><para>String</para></entry> + <entry><para>false</para></entry> + <entry><para>false</para></entry> + </row> + <row> + <entry></entry> + <entry><para><emphasis role="bold">Number</emphasis></para></entry> + <entry><para>Number if can be converted, else false</para></entry> + <entry><para>Number</para></entry> + <entry><para>false</para></entry> + <entry><para>false</para></entry> + </row> + <row> + <entry><para><emphasis role="bold">Type</emphasis></para></entry> + <entry><para><emphasis role="bold">Array</emphasis></para></entry> + <entry><para>false</para></entry> + <entry><para>false</para></entry> + <entry><para>Array</para></entry> + <entry><para>false</para></entry> + </row> + <row> + <entry><para><emphasis role="bold">Requested:</emphasis></para></entry> + <entry><para><emphasis role="bold">Scalar</emphasis></para></entry> + <entry><para>Scalar</para></entry> + <entry><para>Scalar</para></entry> + <entry><para>false</para></entry> + <entry><para>false</para></entry> + </row> + <row> + <entry></entry> + <entry><para><emphasis role="bold">Undefined</emphasis></para></entry> + <entry><para>String</para></entry> + <entry><para>Number</para></entry> + <entry><para>Array</para></entry> + <entry><para>Undefined</para></entry> + </row> + <row> + <entry></entry> + <entry><para><emphasis role="bold">Value Cookie</emphasis></para></entry> + <entry><para>false</para></entry> + <entry><para>false</para></entry> + <entry><para>false</para> + </entry><entry><para>false</para></entry> + </row> + </tbody> +</tgroup> +</informaltable> +@end docbook + @ifnotplaintext +@ifnotdocbook @float Table,table-value-types-returned @caption{Value Types Returned} @multitable @columnfractions .50 .50 @@ -29834,6 +30386,7 @@ value type, as appropriate. This behavior is summarized in @item @tab @b{Value Cookie} @tab false @tab false @tab false @tab false @end multitable @end float +@end ifnotdocbook @end ifnotplaintext @ifplaintext @float Table,table-value-types-returned @@ -29864,45 +30417,46 @@ value type, as appropriate. This behavior is summarized in @end float @end ifplaintext -@node Constructor Functions -@subsection Constructor Functions and Convenience Macros +@node Memory Allocation Functions +@subsection Memory Allocation Functions and Convenience Macros +@cindex allocating memory for extensions +@cindex extensions, allocating memory -The API provides a number of @dfn{constructor} functions for creating -string and numeric values, as well as a number of convenience macros. -This @value{SUBSECTION} presents them all as function prototypes, in -the way that extension code would use them. +The API provides a number of @dfn{memory allocation} functions for +allocating memory that can be passed to @command{gawk}, as well as a number of +convenience macros. @table @code -@item static inline awk_value_t * -@itemx make_const_string(const char *string, size_t length, awk_value_t *result) -This function creates a string value in the @code{awk_value_t} variable -pointed to by @code{result}. It expects @code{string} to be a C string constant -(or other string data), and automatically creates a @emph{copy} of the data -for storage in @code{result}. It returns @code{result}. +@item void *gawk_malloc(size_t size); +Call @command{gawk}-provided @code{api_malloc()} to allocate storage that may +be passed to @command{gawk}. -@item static inline awk_value_t * -@itemx make_malloced_string(const char *string, size_t length, awk_value_t *result) -This function creates a string value in the @code{awk_value_t} variable -pointed to by @code{result}. It expects @code{string} to be a @samp{char *} -value pointing to data previously obtained from @code{malloc()}. The idea here -is that the data is passed directly to @command{gawk}, which assumes -responsibility for it. It returns @code{result}. +@item void *gawk_calloc(size_t nmemb, size_t size); +Call @command{gawk}-provided @code{api_calloc()} to allocate storage that may +be passed to @command{gawk}. -@item static inline awk_value_t * -@itemx make_null_string(awk_value_t *result) -This specialized function creates a null string (the ``undefined'' value) -in the @code{awk_value_t} variable pointed to by @code{result}. -It returns @code{result}. +@item void *gawk_realloc(void *ptr, size_t size); +Call @command{gawk}-provided @code{api_realloc()} to allocate storage that may +be passed to @command{gawk}. -@item static inline awk_value_t * -@itemx make_number(double num, awk_value_t *result) -This function simply creates a numeric value in the @code{awk_value_t} variable -pointed to by @code{result}. +@item void gawk_free(void *ptr); +Call @command{gawk}-provided @code{api_free()} to release storage that was +allocated with @code{gawk_malloc()}, @code{gawk_calloc()} or @code{gawk_realloc()}. @end table -Two convenience macros may be used for allocating storage from @code{malloc()} -and @code{realloc()}. If the allocation fails, they cause @command{gawk} to -exit with a fatal error message. They should be used as if they were +The API has to provide these functions because it is possible +for an extension to be compiled and linked against a different +version of the C library than was used for the @command{gawk} +executable.@footnote{This is more common on MS-Windows systems, but +can happen on Unix-like systems as well.} If @command{gawk} were +to use its version of @code{free()} when the memory came from an +unrelated version of @code{malloc()}, unexpected behavior would +likely result. + +Two convenience macros may be used for allocating storage +from the API-provided function pointers @code{api_malloc()} and +@code{api_realloc()}. If the allocation fails, they cause @command{gawk} +to exit with a fatal error message. They should be used as if they were procedure calls that do not return a value. @table @code @@ -29914,7 +30468,7 @@ The arguments to this macro are as follows: The pointer variable to point at the allocated storage. @item type -The type of the pointer variable, used to create a cast for the call to @code{malloc()}. +The type of the pointer variable, used to create a cast for the call to @code{api_malloc()}. @item size The total number of bytes to be allocated. @@ -29938,13 +30492,51 @@ make_malloced_string(message, strlen(message), & result); @end example @item #define erealloc(pointer, type, size, message) @dots{} -This is like @code{emalloc()}, but it calls @code{realloc()}, -instead of @code{malloc()}. +This is like @code{emalloc()}, but it calls @code{api_realloc()}, +instead of @code{api_malloc()}. The arguments are the same as for the @code{emalloc()} macro. @end table +@node Constructor Functions +@subsection Constructor Functions + +The API provides a number of @dfn{constructor} functions for creating +string and numeric values, as well as a number of convenience macros. +This @value{SUBSECTION} presents them all as function prototypes, in +the way that extension code would use them. + +@table @code +@item static inline awk_value_t * +@itemx make_const_string(const char *string, size_t length, awk_value_t *result) +This function creates a string value in the @code{awk_value_t} variable +pointed to by @code{result}. It expects @code{string} to be a C string constant +(or other string data), and automatically creates a @emph{copy} of the data +for storage in @code{result}. It returns @code{result}. + +@item static inline awk_value_t * +@itemx make_malloced_string(const char *string, size_t length, awk_value_t *result) +This function creates a string value in the @code{awk_value_t} variable +pointed to by @code{result}. It expects @code{string} to be a @samp{char *} +value pointing to data previously obtained from the api-provided functions @code{api_malloc()}, @code{api_calloc()} or @code{api_realloc()}. The idea here +is that the data is passed directly to @command{gawk}, which assumes +responsibility for it. It returns @code{result}. + +@item static inline awk_value_t * +@itemx make_null_string(awk_value_t *result) +This specialized function creates a null string (the ``undefined'' value) +in the @code{awk_value_t} variable pointed to by @code{result}. +It returns @code{result}. + +@item static inline awk_value_t * +@itemx make_number(double num, awk_value_t *result) +This function simply creates a numeric value in the @code{awk_value_t} variable +pointed to by @code{result}. +@end table + @node Registration Functions @subsection Registration Functions +@cindex register extension +@cindex extension registration This @value{SECTION} describes the API functions for registering parts of your extension with @command{gawk}. @@ -29989,8 +30581,8 @@ Letter case in function names is significant. This is a pointer to the C function that provides the desired functionality. The function must fill in the result with either a number -or a string. @command{awk} takes ownership of any string memory. -As mentioned earlier, string memory @strong{must} come from @code{malloc()}. +or a string. @command{gawk} takes ownership of any string memory. +As mentioned earlier, string memory @strong{must} come from the api-provided functions @code{api_malloc()}, @code{api_calloc()} or @code{api_realloc()}. The @code{num_actual_args} argument tells the C function how many actual parameters were passed from the calling @command{awk} code. @@ -30066,6 +30658,7 @@ is invoked with the @option{--version} option. @node Input Parsers @subsubsection Customized Input Parsers +@cindex customized input parser By default, @command{gawk} reads text files as its input. It uses the value of @code{RS} to find the end of the record, and then uses @code{FS} @@ -30313,7 +30906,9 @@ Register the input parser pointed to by @code{input_parser} with @node Output Wrappers @subsubsection Customized Output Wrappers +@cindex customized output wrapper +@cindex output wrapper An @dfn{output wrapper} is the mirror image of an input parser. It allows an extension to take over the output to a file opened with the @samp{>} or @samp{>>} I/O redirection operators (@pxref{Redirection}). @@ -30427,6 +31022,7 @@ Register the output wrapper pointed to by @code{output_wrapper} with @node Two-way processors @subsubsection Customized Two-way Processors +@cindex customized two-way processor A @dfn{two-way processor} combines an input parser and an output wrapper for two-way I/O with the @samp{|&} operator (@pxref{Redirection}). It makes identical @@ -30484,6 +31080,8 @@ Register the two-way processor pointed to by @code{two_way_processor} with @node Printing Messages @subsection Printing Messages +@cindex printing messages from extensions +@cindex messages from extensions You can print different kinds of warning messages from your extension, as described below. Note that for these functions, @@ -30557,6 +31155,7 @@ for more information on creating arrays. @node Symbol Table Access @subsection Symbol Table Access +@cindex accessing global variables from extensions Two sets of routines provide access to global variables, and one set allows you to create and release cached values. @@ -30602,6 +31201,13 @@ An extension can look up the value of @command{gawk}'s special variables. However, with the exception of the @code{PROCINFO} array, an extension cannot change any of those variables. +@quotation NOTE +It is possible for the lookup of @code{PROCINFO} to fail. This happens if +the @command{awk} program being run does not reference @code{PROCINFO}; +in this case @command{gawk} doesn't bother to create the array and +populate it. +@end quotation + @node Symbol table by cookie @subsubsection Variable Access and Update by Cookie @@ -30728,7 +31334,7 @@ assign those values to variables using @code{sym_update()} or @code{sym_update_scalar()}, as you like. However, you can understand the point of cached values if you remember that -@emph{every} string value's storage @emph{must} come from @code{malloc()}. +@emph{every} string value's storage @emph{must} come from @code{api_malloc()}, @code{api_calloc()} or @code{api_realloc()}. If you have 20 variables, all of which have the same string value, you must create 20 identical copies of the string.@footnote{Numeric values are clearly less problematic, requiring only a C @code{double} to store.} @@ -30814,6 +31420,7 @@ you should release any cached values that you created, using @node Array Manipulation @subsection Array Manipulation +@cindex array manipulation in extensions The primary data structure@footnote{Okay, the only data structure.} in @command{awk} is the associative array (@pxref{Arrays}). @@ -30925,7 +31532,7 @@ requires that you understand how such values are converted to strings (@pxref{Conversion}); thus using integral values is safest. As with @emph{all} strings passed into @code{gawk} from an extension, -the string value of @code{index} must come from @code{malloc()}, and +the string value of @code{index} must come from the API-provided functions @code{api_malloc()}, @code{api_calloc()} or @code{api_realloc()} and @command{gawk} releases the storage. @item awk_bool_t set_array_element(awk_array_t a_cookie, @@ -31393,6 +32000,8 @@ information about how @command{gawk} was invoked. @node Extension Versioning @subsubsection API Version Constants and Variables +@cindex API version +@cindex extension API version The API provides both a ``major'' and a ``minor'' version number. The API versions are available at compile time as constants: @@ -31446,6 +32055,8 @@ provided in @file{gawkapi.h} (discussed later, in @node Extension API Informational Variables @subsubsection Informational Variables +@cindex API informational variables +@cindex extension API informational variables The API provides access to several variables that describe whether the corresponding command-line options were enabled when @@ -31591,6 +32202,8 @@ the version string with @command{gawk}. @node Finding Extensions @section How @command{gawk} Finds Extensions +@cindex extension search path +@cindex finding extensions Compiled extensions have to be installed in a directory where @command{gawk} can find them. If @command{gawk} is configured and @@ -31601,6 +32214,7 @@ path with a list of directories to search for compiled extensions. @node Extension Example @section Example: Some File Functions +@cindex extension example @quotation @i{No matter where you go, there you are.} @@ -32059,7 +32673,7 @@ do_stat(int nargs, awk_value_t *result) awk_array_t array; int ret; struct stat sbuf; - /* default is stat() */ + /* default is lstat() */ int (*statfunc)(const char *path, struct stat *sbuf) = lstat; assert(result != NULL); @@ -32245,6 +32859,7 @@ $ @kbd{AWKLIBPATH=$PWD gawk -f testff.awk} @node Extension Samples @section The Sample Extensions In The @command{gawk} Distribution +@cindex extensions distributed with @command{gawk} This @value{SECTION} provides brief overviews of the sample extensions that come in the @command{gawk} distribution. Some of them are intended @@ -32287,7 +32902,7 @@ upon success or less than zero upon error. In the latter case it updates @code{ERRNO}. @cindex @code{stat()} extension function -@item result = stat("/some/path", statdata [, follow]) +@item result = stat("/some/path", statdata @r{[}, follow@r{]}) The @code{stat()} function provides a hook into the @code{stat()} system call. It returns zero upon success or less than zero upon error. @@ -32497,19 +33112,23 @@ See @file{test/fts.awk} in the @command{gawk} distribution for an example. @node Extension Sample Fnmatch @subsection Interface To @code{fnmatch()} -@cindex @code{fnmatch()} extension function This extension provides an interface to the C library @code{fnmatch()} function. The usage is: -@example -@@load "fnmatch" +@table @code +@item @@load "fnmatch" +This is how you load the extension. -result = fnmatch(pattern, string, flags) -@end example +@cindex @code{fnmatch()} extension function +@item result = fnmatch(pattern, string, flags) +The return value is zero on success, @code{FNM_NOMATCH} +if the string did not match the pattern, or +a different non-zero value if an error occurred. +@end table -The @code{fnmatch} extension adds a single function named -@code{fnmatch()}, one constant (@code{FNM_NOMATCH}), and an array of -flag values named @code{FNM}. +Besides the @code{fnmatch()} function, the @code{fnmatch} extension +adds one constant (@code{FNM_NOMATCH}), and an array of flag values +named @code{FNM}. The arguments to @code{fnmatch()} are: @@ -32525,10 +33144,6 @@ Either zero, or the bitwise OR of one or more of the flags in the @code{FNM} array. @end table -The return value is zero on success, @code{FNM_NOMATCH} -if the string did not match the pattern, or -a different non-zero value if an error occurred. - The flags are follows: @multitable @columnfractions .25 .75 @@ -32572,15 +33187,15 @@ This is how you load the extension. @cindex @code{fork()} extension function @item pid = fork() -This function creates a new process. The return value is the zero in the -child and the process-id number of the child in the parent, or @minus{}1 +This function creates a new process. The return value is zero in the +child and the process-ID number of the child in the parent, or @minus{}1 upon error. In the latter case, @code{ERRNO} indicates the problem. In the child, @code{PROCINFO["pid"]} and @code{PROCINFO["ppid"]} are updated to reflect the correct values. @cindex @code{waitpid()} extension function @item ret = waitpid(pid) -This function takes a numeric argument, which is the process-id to +This function takes a numeric argument, which is the process-ID to wait for. The return value is that of the @code{waitpid()} system call. @@ -32836,7 +33451,7 @@ ret = reada("arraydump.bin", array) @subsection Reading An Entire File The @code{readfile} extension adds a single function -named @code{readfile()}: +named @code{readfile()}, and an input parser: @table @code @item @@load "readfile" @@ -32847,6 +33462,12 @@ This is how you load the extension. The argument is the name of the file to read. The return value is a string containing the entire contents of the requested file. Upon error, the function returns the empty string and sets @code{ERRNO}. + +@item BEGIN @{ PROCINFO["readfile"] = 1 @} +In addition, the extension adds an input parser that is activated if +@code{PROCINFO["readfile"]} exists. +When activated, each input file is returned in its entirety as @code{$0}. +@code{RT} is set to the null string. @end table Here is an example: @@ -32905,6 +33526,8 @@ tries to use @code{nanosleep()} or @code{select()} to implement the delay. @node gawkextlib @section The @code{gawkextlib} Project +@cindex @code{gawkextlib} +@cindex extensions, where to find @cindex @code{gawkextlib} project The @uref{http://sourceforge.net/projects/gawkextlib/, @code{gawkextlib}} @@ -32938,6 +33561,7 @@ The @code{time} extension described earlier (@pxref{Extension Sample Time}) was originally from this project but has been moved in to the main @command{gawk} distribution. +@cindex @command{git} utility You can check out the code for the @code{gawkextlib} project using the @uref{http://git-scm.com, GIT} distributed source code control system. The command is as follows: @@ -34204,7 +34828,7 @@ The @option{-i} and @option{--include} options load @command{awk} library files. @item -The @option{-l} and @option{--load} options for load compiled dynamic extensions. +The @option{-l} and @option{--load} options load compiled dynamic extensions. @item The @option{-M} and @option{--bignum} options enable MPFR. @@ -34225,7 +34849,7 @@ Support for high precision arithmetic with MPFR. @item The @code{and()}, @code{or()} and @code{xor()} functions -allow any number of arguments, +changed to allow any number of arguments, with a minimum of two (@pxref{Bitwise Functions}). @@ -34250,18 +34874,18 @@ the three most widely-used freely available versions of @command{awk} @multitable {@file{/dev/stderr} special file} {BWK Awk} {Mawk} {GNU Awk} @headitem Feature @tab BWK Awk @tab Mawk @tab GNU Awk @item @samp{\x} Escape sequence @tab X @tab X @tab X -@item @code{RS} as regexp @tab @tab X @tab X @item @code{FS} as null string @tab X @tab X @tab X @item @file{/dev/stdin} special file @tab X @tab X @tab X @item @file{/dev/stdout} special file @tab X @tab X @tab X @item @file{/dev/stderr} special file @tab X @tab X @tab X -@item @code{**} and @code{**=} operators @tab X @tab @tab X -@item @code{fflush()} function @tab X @tab X @tab X -@item @code{func} keyword @tab X @tab @tab X -@item @code{nextfile} statement @tab X @tab X @tab X @item @code{delete} without subscript @tab X @tab X @tab X +@item @code{fflush()} function @tab X @tab X @tab X @item @code{length()} of an array @tab X @tab X @tab X +@item @code{nextfile} statement @tab X @tab X @tab X +@item @code{**} and @code{**=} operators @tab X @tab @tab X +@item @code{func} keyword @tab X @tab @tab X @item @code{BINMODE} variable @tab @tab X @tab X +@item @code{RS} as regexp @tab @tab X @tab X @item Time related functions @tab @tab X @tab X @end multitable @@ -34292,7 +34916,7 @@ as working in this fashion, and in particular, would teach that the that @samp{[A-Z]} was the ``correct'' way to match uppercase letters. And indeed, this was true.@footnote{And Life was good.} -The 1993 POSIX standard introduced the idea of locales (@pxref{Locales}). +The 1992 POSIX standard introduced the idea of locales (@pxref{Locales}). Since many locales include other letters besides the plain twenty-six letters of the American English alphabet, the POSIX standard added character classes (@pxref{Bracket Expressions}) as a way to match @@ -34331,6 +34955,7 @@ This output is unexpected, since the @samp{bc} at the end of This result is due to the locale setting (and thus you may not see it on your system). +@cindex Unicode Similar considerations apply to other ranges. For example, @samp{["-/]} is perfectly valid in ASCII, but is not valid in many Unicode locales, such as @samp{en_US.UTF-8}. @@ -34344,16 +34969,17 @@ vendors started implementing non-ASCII locales, @emph{and making them the default}. Perhaps the most frequently asked question became something like ``why does @samp{[A-Z]} match lowercase letters?!?'' +@cindex Berry, Karl This situation existed for close to 10 years, if not more, and the @command{gawk} maintainer grew weary of trying to explain that @command{gawk} was being nicely standards-compliant, and that the issue was in the user's locale. During the development of version 4.0, he modified @command{gawk} to always treat ranges in the original, pre-POSIX fashion, unless @option{--posix} was used (@pxref{Options}).@footnote{And -thus was born the Campain for Rational Range Interpretation (or RRI). A number -of GNU tools, such as @command{grep} and @command{sed}, have either -implemented this change, or will soon. Thanks to Karl Berry for coining the phrase -``Rational Range Interpretation.''} +thus was born the Campaign for Rational Range Interpretation (or +RRI). A number of GNU tools have either implemented this change, +or will soon. Thanks to Karl Berry for coining the phrase ``Rational +Range Interpretation.''} Fortunately, shortly before the final release of @command{gawk} 4.0, the maintainer learned that the 2008 standard had changed the @@ -34366,7 +34992,7 @@ and By using this lovely technical term, the standard gives license to implementors to implement ranges in whatever way they choose. The @command{gawk} maintainer chose to apply the pre-POSIX meaning in all -cases: the default regexp matching; with @option{--traditional}, and with +cases: the default regexp matching; with @option{--traditional} and with @option{--posix}; in all cases, @command{gawk} remains POSIX compliant. @node Contributors @@ -34566,6 +35192,11 @@ environments. Anders Wallin helped keep the VMS port going for several years. @item +@cindex Gordon, Assaf +Assaf Gordon contributed the code to implement the +@option{--sandbox} option. + +@item @cindex Haque, John John Haque made the following contributions: @@ -34609,6 +35240,11 @@ Arnold Robbins and Andrew Schorr, with notable contributions from the rest of the development team. @item +@cindex Colombo, Antonio +Antonio Giovanni Colombo rewrote a number of examples in the early +chapters that were severely dated, for which I am incredibly grateful. + +@item @cindex Robbins, Arnold Arnold Robbins has been working on @command{gawk} since 1988, at first @@ -35007,7 +35643,7 @@ please send in a bug report (@pxref{Bugs}). Of course, once you've built @command{gawk}, it is likely that you will wish to install it. To do so, you need to run the command @samp{make -check}, as a user with the appropriate permissions. How to do this +install}, as a user with the appropriate permissions. How to do this varies by system, but on many systems you can use the @command{sudo} command to do so. The command then becomes @samp{sudo make install}. It is likely that you will be asked for your password, and you will have @@ -35333,11 +35969,10 @@ multibyte functionality is not available. @c STARTOFRANGE pcgawon @cindex PC operating systems, @command{gawk} on -With the exception of the Cygwin environment, -the @samp{|&} operator and TCP/IP networking -(@pxref{TCP/IP Networking}) -are not supported for MS-DOS or MS-Windows. EMX (OS/2 only) does support -at least the @samp{|&} operator. +Under MS-DOS and MS-Windows, the Cygwin and MinGW environments support +both the @samp{|&} operator and TCP/IP networking +(@pxref{TCP/IP Networking}). +EMX (OS/2 only) supports at least the @samp{|&} operator. @cindex search paths @cindex search paths, for source files @@ -35467,7 +36102,7 @@ moved into the @code{BEGIN} rule. @command{gawk} can be built and used ``out of the box'' under MS-Windows if you are using the @uref{http://www.cygwin.com, Cygwin environment}. -This environment provides an excellent simulation of Unix, using the +This environment provides an excellent simulation of GNU/Linux, using the GNU tools, such as Bash, the GNU Compiler Collection (GCC), GNU Make, and other GNU programs. Compilation and installation for Cygwin is the same as for a Unix system: @@ -35483,13 +36118,6 @@ When compared to GNU/Linux on the same system, the @samp{configure} step on Cygwin takes considerably longer. However, it does finish, and then the @samp{make} proceeds as usual. -@quotation NOTE -The @samp{|&} operator and TCP/IP networking -(@pxref{TCP/IP Networking}) -are fully supported in the Cygwin environment. This is not true -for any other environment on MS-Windows. -@end quotation - @node MSYS @appendixsubsubsec Using @command{gawk} In The MSYS Environment @@ -35557,21 +36185,14 @@ can better handle @code{ODS-5} volumes with upper- and lowercase filenames. With @code{ODS-5} volumes and extended parsing enabled, the case of the target parameter may need to be exact. -Older versions of @command{gawk} could be built with VAX C or -GNU C on VAX/VMS, as well as with DEC C, but that is no longer -supported. DEC C (also briefly known as ``Compaq C'' and now known -as ``HP C,'' but referred to here as ``DEC C'') is required. Both -@code{vmsbuild.com} and @code{descrip.mms} contain some obsolete support -for the older compilers but are set up to use DEC C by default. - @command{gawk} has been tested under VAX/VMS 7.3 and Alpha/VMS 7.3-1 using Compaq C V6.4, and Alpha/VMS 7.3, Alpha/VMS 7.3-2, and IA64/VMS 8.3. The most recent builds used HP C V7.3 on Alpha VMS 8.3 and both Alpha and IA64 VMS 8.4 used HP C 7.3.@footnote{The IA64 architecture is also known as ``Itanium.''} -Work is currently being done for a procedure to build @command{gawk} and create -a PCSI kit for compatible with the GNV product. +The @file{[.vms]gawk_build_steps.txt} provides information on how to build +@command{gawk} into a PCSI kit that is compatible with the GNV product. @node VMS Dynamic Extensions @appendixsubsubsec Compiling @command{gawk} Dynamic Extensions on VMS @@ -35668,7 +36289,7 @@ add the @command{gawk} and @command{awk} to the system wide @samp{DCLTABLES}. The DCL syntax is documented in the @file{gawk.hlp} file. -Optionally, @file{gawk.hlp} entry can be loaded into a VMS help library: +Optionally, the @file{gawk.hlp} entry can be loaded into a VMS help library: @example $ @kbd{LIBRARY/HELP sys$help:helplib [.vms]gawk.hlp} @@ -35923,22 +36544,23 @@ file should be considered authoritative if it conflicts with this The people maintaining the non-Unix ports of @command{gawk} are as follows: -@multitable {MS-Windows with MINGW} {123456789012345678901234567890123456789001234567890} +@c put the index entries outside the table, for docbook @cindex Deifik, Scott +@cindex Zaretskii, Eli +@cindex Buening, Andreas +@cindex Rankin, Pat +@cindex Malmberg, John +@cindex Pitts, Dave +@multitable {MS-Windows with MINGW} {123456789012345678901234567890123456789001234567890} @item MS-DOS with DJGPP @tab Scott Deifik, @EMAIL{scottd.mail@@sbcglobal.net,scottd dot mail at sbcglobal dot net}. -@cindex Zaretskii, Eli @item MS-Windows with MINGW @tab Eli Zaretskii, @EMAIL{eliz@@gnu.org,eliz at gnu dot org}. -@cindex Buening, Andreas @item OS/2 @tab Andreas Buening, @EMAIL{andreas.buening@@nexgo.de,andreas dot buening at nexgo dot de}. -@cindex Rankin, Pat -@cindex Malmberg, John @item VMS @tab Pat Rankin, @EMAIL{r.pat.rankin@@gmail.com,r.pat.rankin at gmail.com}, and John Malmberg, @EMAIL{wb8tyw@@qsl.net,wb8tyw at qsl.net}. -@cindex Pitts, Dave @item z/OS (OS/390) @tab Dave Pitts, @EMAIL{dpitts@@cozx.com,dpitts at cozx dot com}. @end multitable @@ -35973,7 +36595,7 @@ This @value{SECTION} briefly describes where to get them: @cindex Kernighan, Brian @cindex source code, Brian Kernighan's @command{awk} @cindex @command{awk}, versions of, See Also Brian Kernighan's @command{awk} -@cindex Brian Kernighan's @command{awk} +@cindex Brian Kernighan's @command{awk}, source code @item Unix @command{awk} Brian Kernighan, one of the original designers of Unix @command{awk}, has made his implementation of @@ -35993,6 +36615,7 @@ It is available in several archive formats: @uref{http://www.cs.princeton.edu/~bwk/btl.mirror/awk.zip} @end table +@cindex @command{git} utility You can also retrieve it from Git Hub: @example @@ -36012,7 +36635,7 @@ from GCC (the GNU Compiler Collection) works quite nicely. for a list of extensions in this @command{awk} that are not in POSIX @command{awk}. @cindex Brennan, Michael -@cindex @command{mawk} program +@cindex @command{mawk} utility @cindex source code, @command{mawk} @item @command{mawk} Michael Brennan wrote an independent implementation of @command{awk}, @@ -36058,7 +36681,7 @@ To get @command{awka}, go to @url{http://sourceforge.net/projects/awka}. The project seems to be frozen; no new code changes have been made since approximately 2003. -@cindex Beebe, Nelson +@cindex Beebe, Nelson H.F.@: @cindex @command{pawk} (profiling version of Brian Kernighan's @command{awk}) @cindex source code, @command{pawk} @item @command{pawk} @@ -36121,6 +36744,7 @@ This is an embeddable @command{awk} interpreter derived from @uref{http://repo.hu/projects/libmawk/}. @item @code{pawk} +@cindex source code, @command{pawk} (Python version) @cindex @code{pawk}, @command{awk}-like facilities for Python This is a Python module that claims to bring @command{awk}-like features to Python. See @uref{https://github.com/alecthomas/pawk} @@ -36226,6 +36850,7 @@ As @command{gawk} is Free Software, the source code is always available. @ref{Gawk Distribution}, describes how to get and build the formal, released versions of @command{gawk}. +@cindex @command{git} utility However, if you want to modify @command{gawk} and contribute back your changes, you will probably wish to work with the development version. To do so, you will need to access the @command{gawk} source code @@ -36401,6 +37026,7 @@ If possible, please update the @command{man} page as well. You will also have to sign paperwork for your documentation changes. +@cindex @command{git} utility @item Submit changes as unified diffs. Use @samp{diff -u -r -N} to compare @@ -36534,6 +37160,8 @@ coding style and brace layout that suits your taste. @node Derived Files @appendixsubsec Why Generated Files Are Kept In @command{git} +@c STARTOFRANGE gawkgit +@cindex @command{git}, use of for @command{gawk} source code @c From emails written March 22, 2012, to the gawk developers list. If you look at the @command{gawk} source in the @command{git} @@ -36713,7 +37341,7 @@ wget http://git.savannah.gnu.org/cgit/gawk.git/snapshot/gawk-@var{branchname}.ta @noindent to retrieve a snapshot of the given branch. - +@c ENDOFRANGE gawkgit @node Future Extensions @appendixsec Probable Future Extensions @@ -37084,8 +37712,15 @@ other introductory texts that you should refer to instead.) @cindex processing data At the most basic level, the job of a program is to process -some input data and produce results. See @ref{figure-general-flow}. +some input data and produce results. +@ifnotdocbook +See @ref{figure-general-flow}. +@end ifnotdocbook +@ifdocbook +See @inlineraw{docbook, <xref linkend="figure-general-flow"/>}. +@end ifdocbook +@ifnotdocbook @float Figure,figure-general-flow @caption{General Program Flow} @ifinfo @@ -37095,6 +37730,14 @@ some input data and produce results. See @ref{figure-general-flow}. @center @image{general-program, , , General program flow} @end ifnotinfo @end float +@end ifnotdocbook + +@docbook +<figure id="figure-general-flow"> +<title>General Program Flow</title> +<graphic fileref="general-program.eps"/> +</figure> +@end docbook @cindex compiled programs @cindex interpreted programs @@ -37110,9 +37753,15 @@ instructions in your program to process the data. @cindex programming, basic steps When you write a program, it usually consists -of the following, very basic set of steps, as shown -in @ref{figure-process-flow}: +of the following, very basic set of steps, +@ifnotdocbook +as shown in @ref{figure-process-flow}: +@end ifnotdocbook +@ifdocbook +as shown in @inlineraw{docbook <xref linkend="figure-process-flow"/>}: +@end ifdocbook +@ifnotdocbook @float Figure,figure-process-flow @caption{Basic Program Steps} @ifinfo @@ -37122,6 +37771,14 @@ in @ref{figure-process-flow}: @center @image{process-flow, , , Basic Program Stages} @end ifnotinfo @end float +@end ifnotdocbook + +@docbook +<figure id="figure-process-flow"> +<title>Basic Program Stages</title> +<graphic fileref="process-flow.eps"/> +</figure> +@end docbook @table @asis @item Initialization @@ -37292,7 +37949,7 @@ better written in another language. You can get it from @uref{http://awk.info/?awk100/aaa}. @cindex Ada programming language -@cindex Programming languages, Ada +@cindex programming languages, Ada @item Ada A programming language originally defined by the U.S.@: Department of Defense for embedded programming. It was designed to enforce good @@ -37360,9 +38017,6 @@ The GNU version of the standard shell @end ifinfo See also ``Bourne Shell.'' -@item BBS -See ``Bulletin Board System.'' - @item Bit Short for ``Binary Digit.'' All values in computer memory ultimately reduce to binary digits: values @@ -37437,11 +38091,6 @@ Changing some of them affects @command{awk}'s running environment. @item Braces See ``Curly Braces.'' -@item Bulletin Board System -A computer system allowing users to log in and read and/or leave messages -for other users of the system, much like leaving paper notes on a bulletin -board. - @item C The system programming language that most GNU software is written in. The @command{awk} programming language has C-like syntax, and this @value{DOCUMENT} @@ -37468,6 +38117,8 @@ The @uref{http://www.unicode.org, Unicode character set} is becoming increasingly popular and standard, and is particularly widely used on GNU/Linux systems. +@cindex Kernighan, Brian +@cindex Bentley, Jon @cindex @command{chem} utility @item CHEM A preprocessor for @command{pic} that reads descriptions of molecules @@ -37604,7 +38255,7 @@ ordinary expression. It could be a string constant, such as (@xref{Computed Regexps}.) @item Environment -A collection of strings, of the form @var{name@code{=}val}, that each +A collection of strings, of the form @var{name}@code{=}@code{val}, that each program has available to it. Users generally place values into the environment in order to provide information to various programs. Typical examples are the environment variables @env{HOME} and @env{PATH}. @@ -37773,7 +38424,7 @@ information about the name of the organization and its language-independent three-letter acronym. @cindex Java programming language -@cindex Programming languages, Java +@cindex programming languages, Java @item Java A modern programming language originally developed by Sun Microsystems (now Oracle) supporting Object-Oriented programming. Although usually @@ -38060,7 +38711,12 @@ record or a string. @c The GNU General Public License. @node Copying @unnumbered GNU General Public License +@ifnotdocbook @center Version 3, 29 June 2007 +@end ifnotdocbook +@docbook +<subtitle>Version 3, 29 June 2007</subtitle> +@end docbook @c This file is intended to be included within another document, @c hence no sectioning command or @node. @@ -38785,10 +39441,17 @@ first, please read @url{http://www.gnu.org/philosophy/why-not-lgpl.html}. @c The GNU Free Documentation License. @node GNU Free Documentation License @unnumbered GNU Free Documentation License +@ifnotdocbook +@center Version 1.3, 3 November 2008 +@end ifnotdocbook + +@docbook +<subtitle>Version 1.3, 3 November 2008</subtitle> +@end docbook + @cindex FDL (Free Documentation License) @cindex Free Documentation License (FDL) @cindex GNU Free Documentation License -@center Version 1.3, 3 November 2008 @c This file is intended to be included within another document, @c hence no sectioning command or @node. @@ -39293,8 +39956,10 @@ to permit their use in free software. @c ispell-local-pdict: "ispell-dict" @c End: +@ifnotdocbook @node Index @unnumbered Index +@end ifnotdocbook @printindex cp @bye @@ -39405,8 +40070,6 @@ Suggestions: % Next edition: % 1. Standardize the error messages from the functions and programs % in the two sample code chapters. -% 2. Nuke the BBS stuff and use something that won't be obsolete -% 3. Turn the advanced notes into sidebars by using @cartouche Better sidebars can almost sort of be done with: @@ -39438,4 +40101,3 @@ But to use it you have to say } which sorta sucks. - diff --git a/doc/gawktexi.in b/doc/gawktexi.in index 6b9acdea..791f787f 100644 --- a/doc/gawktexi.in +++ b/doc/gawktexi.in @@ -35,9 +35,9 @@ @c applies to and all the info about who's publishing this edition @c These apply across the board. -@set UPDATE-MONTH February, 2014 +@set UPDATE-MONTH April, 2014 @set VERSION 4.1 -@set PATCHLEVEL 0 +@set PATCHLEVEL 1 @set FSF @@ -111,11 +111,19 @@ @end ifnottex @ifnottex +@ifnotdocbook @macro ii{text} @i{\text\} @end macro +@end ifnotdocbook @end ifnottex +@ifdocbook +@macro ii{text} +@inlineraw{docbook,<lineannotation>\text\</lineannotation>} +@end macro +@end ifdocbook + @c For HTML, spell out email addresses, to avoid problems with @c address harvesters for spammers. @ifhtml @@ -129,9 +137,36 @@ @end macro @end ifnothtml +@c Indexing macros +@ifinfo + +@macro cindexawkfunc{name} +@cindex @code{\name\} +@end macro + +@macro cindexgawkfunc{name} +@cindex @code{\name\} +@end macro + +@end ifinfo + +@ifnotinfo + +@macro cindexawkfunc{name} +@cindex @code{\name\()} function +@end macro + +@macro cindexgawkfunc{name} +@cindex @code{\name\()} function (@command{gawk}) +@end macro +@end ifnotinfo + @ignore Some comments on the layout for TeX. 1. Use at least texinfo.tex 2014-01-30.15 +2. When using @docbook, if the last line is part of a paragraph, end +it with a space and @c so that the lines won't run together. This is a +quirk of the language / makeinfo, and isn't going to change. @end ignore @c merge the function and variable indexes into the concept index @@ -147,6 +182,10 @@ Some comments on the layout for TeX. @syncodeindex fn cp @syncodeindex vr cp @end ifxml +@ifdocbook +@synindex fn cp +@synindex vr cp +@end ifdocbook @c If "finalout" is commented out, the printed output will show @c black boxes that mark lines that are too long. Thus, it is @@ -158,10 +197,26 @@ Some comments on the layout for TeX. @end iftex @copying -Copyright @copyright{} 1989, 1991, 1992, 1993, 1996, 1997, 1998, 1999, -2000, 2001, 2002, 2003, 2004, 2005, 2007, 2009, 2010, 2011, 2012, 2013, -2014 +@docbook +<para>Published by:</para> + +<literallayout class="normal">Free Software Foundation +51 Franklin Street, Fifth Floor +Boston, MA 02110-1301 USA +Phone: +1-617-542-5942 +Fax: +1-617-542-2652 +Email: <email>gnu@@gnu.org</email> +URL: <ulink url="http://www.gnu.org">http://www.gnu.org/</ulink></literallayout> + +<literallayout class="normal">Copyright © 1989, 1991, 1992, 1993, 1996–2005, 2007, 2009–2014 Free Software Foundation, Inc. +All Rights Reserved.</literallayout> +@end docbook + +@ifnotdocbook +Copyright @copyright{} 1989, 1991, 1992, 1993, 1996--2005, 2007, 2009--2014 @* +Free Software Foundation, Inc. +@end ifnotdocbook @sp 2 This is Edition @value{EDITION} of @cite{@value{TITLE}: @value{SUBTITLE}}, @@ -209,6 +264,7 @@ supports it in developing GNU and promoting software freedom.'' @subtitle @value{UPDATE-MONTH} @author Arnold D. Robbins +@ifnotdocbook @c Include the Distribution inside the titlepage environment so @c that headings are turned off. Headings on and off do not work. @@ -233,6 +289,7 @@ URL: @uref{http://www.gnu.org/} @* ISBN 1-882114-28-0 @* @sp 2 @insertcopying +@end ifnotdocbook @end titlepage @c Thanks to Bob Chassell for directions on doing dedications. @@ -257,6 +314,18 @@ ISBN 1-882114-28-0 @* @headings on @end iftex +@docbook +<dedication> +<simplelist> +<member>To Miriam, for making me complete.</member> +<member>To Chana, for the joy you bring us.</member> +<member>To Rivka, for the exponential increase.</member> +<member>To Nachum, for the added dimension.</member> +<member>To Malka, for the new beginning.</member> +</simplelist> +</dedication> +@end docbook + @iftex @headings off @evenheading @thispage@ @ @ @strong{@value{TITLE}} @| @| @@ -265,6 +334,7 @@ ISBN 1-882114-28-0 @* @ifnottex @ifnotxml +@ifnotdocbook @node Top @top General Introduction @c Preface node should come right after the Top @@ -276,6 +346,7 @@ particular records in a file and perform operations upon them. @insertcopying +@end ifnotdocbook @end ifnotxml @end ifnottex @@ -737,6 +808,7 @@ particular records in a file and perform operations upon them. * Extension API Functions Introduction:: Introduction to the API functions. * General Data Types:: The data types. * Requesting Values:: How to get a value. +* Memory Allocation Functions:: Functions for allocating memory. * Constructor Functions:: Functions for creating values. * Registration Functions:: Functions to register things with @command{gawk}. @@ -799,7 +871,8 @@ particular records in a file and perform operations upon them. version of @command{awk}. * POSIX/GNU:: The extensions in @command{gawk} not in POSIX @command{awk}. -* Feature History:: The history of the features in @command{gawk}. +* Feature History:: The history of the features in + @command{gawk}. * Common Extensions:: Common Extensions Summary. * Ranges and Locales:: How locales used to affect regexp ranges. @@ -971,21 +1044,37 @@ and the AWK prototype becomes the product. The new @command{pgawk} (profiling @command{gawk}), produces program execution counts. I recently experimented with an algorithm that for -@math{n} lines of input, exhibited +@ifnotdocbook +@math{n} +@end ifnotdocbook +@ifdocbook +@i{n} +@end ifdocbook +lines of input, exhibited @tex $\sim\! Cn^2$ @end tex @ifnottex +@ifnotdocbook ~ C n^2 +@end ifnotdocbook @end ifnottex +@docbook +<emphasis>∼ Cn<superscript>2</superscript></emphasis> @c +@end docbook performance, while theory predicted @tex $\sim\! Cn\log n$ @end tex @ifnottex +@ifnotdocbook ~ C n log n +@end ifnotdocbook @end ifnottex +@docbook +<emphasis>∼ Cn log n</emphasis> @c +@end docbook behavior. A few minutes poring over the @file{awkprof.out} profile pinpointed the problem to a single line of code. @command{pgawk} is a welcome addition to @@ -995,6 +1084,7 @@ Arnold has distilled over a decade of experience writing and using AWK programs, and developing @command{gawk}, into this book. If you use AWK or want to learn how, then read this book. +@cindex Brennan, Michael @display Michael Brennan Author of @command{mawk} @@ -1019,6 +1109,7 @@ Such jobs are often easier with @command{awk}. The @command{awk} utility interprets a special-purpose programming language that makes it easy to handle simple data-reformatting jobs. +@cindex Brian Kernighan's @command{awk} The GNU implementation of @command{awk} is called @command{gawk}; if you invoke it with the proper options or environment variables (@pxref{Options}), it is fully @@ -1741,7 +1832,7 @@ significant editorial help for this @value{DOCUMENT} for the 3.1 release of @command{gawk}. @end quotation -@cindex Beebe, Nelson +@cindex Beebe, Nelson H.F.@: @cindex Buening, Andreas @cindex Collado, Manuel @cindex Colombo, Antonio @@ -2034,11 +2125,11 @@ $ @kbd{awk "BEGIN @{ print \"Don't Panic!\" @}"} @print{} Don't Panic! @end example -@cindex quoting -@cindex double quote (@code{"}) -@cindex @code{"} (double quote) -@cindex @code{\} (backslash) -@cindex backslash (@code{\}) +@cindex shell quoting, double quote +@cindex double quote (@code{"}) in shell commands +@cindex @code{"} (double quote) in shell commands +@cindex @code{\} (backslash) in shell commands +@cindex backslash (@code{\}) in shell commands This program does not read any input. The @samp{\} before each of the inner double quotes is necessary because of the shell's quoting rules---in particular because it mixes both single quotes and @@ -2078,8 +2169,7 @@ awk -f @var{source-file} @var{input-file1} @var{input-file2} @dots{} @end example @cindex @option{-f} option -@cindex command line, options -@cindex options, command-line +@cindex command line, option @option{-f} The @option{-f} instructs the @command{awk} utility to get the @command{awk} program from the file @var{source-file}. Any file name can be used for @var{source-file}. For example, you could put the program: @@ -2102,7 +2192,7 @@ does the same thing as this one: awk "BEGIN @{ print \"Don't Panic!\" @}" @end example -@cindex quoting +@cindex quoting in @command{gawk} command lines @noindent This was explained earlier (@pxref{Read Terminal}). @@ -2113,9 +2203,9 @@ program did not have single quotes around it. The quotes are only needed for programs that are provided on the @command{awk} command line. @c STARTOFRANGE sq1x -@cindex single quote (@code{'}) +@cindex single quote (@code{'}) in @command{gawk} command lines @c STARTOFRANGE qs2x -@cindex @code{'} (single quote) +@cindex @code{'} (single quote) in @command{gawk} command lines If you want to clearly identify your @command{awk} program files as such, you can add the extension @file{.awk} to the file name. This doesn't affect the execution of the @command{awk} program but it does make @@ -2225,7 +2315,7 @@ programs, but this usually isn't very useful; the purpose of a comment is to help you or another person understand the program when reading it at a later time. -@cindex quoting +@cindex quoting, for small awk programs @cindex single quote (@code{'}), vs.@: apostrophe @cindex @code{'} (single quote), vs.@: apostrophe @quotation CAUTION @@ -2266,7 +2356,7 @@ The next @value{SUBSECTION} describes the shell's quoting rules. @node Quoting @subsection Shell-Quoting Issues -@cindex quoting, rules for +@cindex shell quoting, rules for @menu * DOS Quoting:: Quoting in Windows Batch Files. @@ -2301,10 +2391,10 @@ that character. The shell removes the backslash and passes the quoted character on to the command. @item -@cindex @code{\} (backslash) -@cindex backslash (@code{\}) -@cindex single quote (@code{'}) -@cindex @code{'} (single quote) +@cindex @code{\} (backslash), in shell commands +@cindex backslash (@code{\}), in shell commands +@cindex single quote (@code{'}), in shell commands +@cindex @code{'} (single quote), in shell commands Single quotes protect everything between the opening and closing quotes. The shell does no interpretation of the quoted text, passing it on verbatim to the command. @@ -2314,8 +2404,8 @@ Refer back to for an example of what happens if you try. @item -@cindex double quote (@code{"}) -@cindex @code{"} (double quote) +@cindex double quote (@code{"}), in shell commands +@cindex @code{"} (double quote), in shell commands Double quotes protect most things between the opening and closing quotes. The shell does at least variable and command substitution on the quoted text. Different shells may do additional kinds of processing on double-quoted text. @@ -2352,7 +2442,7 @@ awk -F "" '@var{program}' @var{files} # correct @end example @noindent -@cindex null strings, quoting and +@cindex null strings in @command{gawk} arguments, quoting and Don't use this: @example @@ -2365,7 +2455,7 @@ as the value of @code{FS}, and the first file name as the text of the program! This results in syntax errors at best, and confusing behavior at worst. @end itemize -@cindex quoting, tricks for +@cindex quoting in @command{gawk} command lines, tricks for Mixing single and double quotes is difficult. You have to resort to shell quoting tricks, like this: @@ -2480,40 +2570,39 @@ gawk "@{ print \"\042\" $0 \"\042\" @}" @var{file} @c For gawk >= 4.0, update these data files. No-one has such slow modems! @cindex input files, examples -@cindex @code{BBS-list} file +@cindex @code{mail-list} file Many of the examples in this @value{DOCUMENT} take their input from two sample -data files. The first, @file{BBS-list}, represents a list of -computer bulletin board systems together with information about those systems. +data files. The first, @file{mail-list}, represents a list of peoples' names +together with their email addresses and information about those people. The second data file, called @file{inventory-shipped}, contains information about monthly shipments. In both files, each line is considered to be one @dfn{record}. -In the data file @file{BBS-list}, each record contains the name of a computer -bulletin board, its phone number, the board's baud rate(s), and a code for -the number of hours it is operational. An @samp{A} in the last column -means the board operates 24 hours a day. A @samp{B} in the last -column means the board only operates on evening and weekend hours. -A @samp{C} means the board operates only on weekends: +In the data file @file{mail-list}, each record contains the name of a person, +his/her phone number, his/her email-address, and a code for their relationship +with the author of the list. An @samp{A} in the last column +means that the person is an acquaintance. An @samp{F} in the last +column means that the person is a friend. +An @samp{R} means that the person is a relative: -@c 2e: Update the baud rates to reflect today's faster modems @example @c system if test ! -d eg ; then mkdir eg ; fi @c system if test ! -d eg/lib ; then mkdir eg/lib ; fi @c system if test ! -d eg/data ; then mkdir eg/data ; fi @c system if test ! -d eg/prog ; then mkdir eg/prog ; fi @c system if test ! -d eg/misc ; then mkdir eg/misc ; fi -@c file eg/data/BBS-list -aardvark 555-5553 1200/300 B -alpo-net 555-3412 2400/1200/300 A -barfly 555-7685 1200/300 A -bites 555-1675 2400/1200/300 A -camelot 555-0542 300 C -core 555-2912 1200/300 C -fooey 555-1234 2400/1200/300 B -foot 555-6699 1200/300 B -macfoo 555-6480 1200/300 A -sdace 555-3430 2400/1200/300 A -sabafoo 555-2127 1200/300 C +@c file eg/data/mail-list +Amelia 555-5553 amelia.zodiacusque@@gmail.com F +Anthony 555-3412 anthony.asserturo@@hotmail.com A +Becky 555-7685 becky.algebrarum@@gmail.com A +Bill 555-1675 bill.drowning@@hotmail.com A +Broderick 555-0542 broderick.aliquotiens@@yahoo.com R +Camilla 555-2912 camilla.infusarum@@skynet.be R +Fabius 555-1234 fabius.undevicesimus@@ucb.edu F +Julie 555-6699 julie.perscrutabor@@skeeve.com F +Martin 555-6480 martin.codicibus@@hotmail.com A +Samuel 555-3430 samuel.lanceolis@@shu.edu A +Jean-Paul 555-2127 jeanpaul.campanorum@@nyu.edu R @c endfile @end example @@ -2555,23 +2644,23 @@ in the directory @file{awklib/eg/data}. @section Some Simple Examples The following command runs a simple @command{awk} program that searches the -input file @file{BBS-list} for the character string @samp{foo} (a +input file @file{mail-list} for the character string @samp{li} (a grouping of characters is usually called a @dfn{string}; the term @dfn{string} is based on similar usage in English, such as ``a string of pearls,'' or ``a string of cars in a train''): @example -awk '/foo/ @{ print $0 @}' BBS-list +awk '/li/ @{ print $0 @}' mail-list @end example @noindent -When lines containing @samp{foo} are found, they are printed because +When lines containing @samp{li} are found, they are printed because @w{@samp{print $0}} means print the current line. (Just @samp{print} by itself means the same thing, so we could have written that instead.) -You will notice that slashes (@samp{/}) surround the string @samp{foo} -in the @command{awk} program. The slashes indicate that @samp{foo} +You will notice that slashes (@samp{/}) surround the string @samp{li} +in the @command{awk} program. The slashes indicate that @samp{li} is the pattern to search for. This type of pattern is called a @dfn{regular expression}, which is covered in more detail later (@pxref{Regexp}). @@ -2583,11 +2672,11 @@ interpret any of it as special shell characters. Here is what this program prints: @example -$ @kbd{awk '/foo/ @{ print $0 @}' BBS-list} -@print{} fooey 555-1234 2400/1200/300 B -@print{} foot 555-6699 1200/300 B -@print{} macfoo 555-6480 1200/300 A -@print{} sabafoo 555-2127 1200/300 C +$ @kbd{awk '/li/ @{ print $0 @}' mail-list} +@print{} Amelia 555-5553 amelia.zodiacusque@@gmail.com F +@print{} Broderick 555-0542 broderick.aliquotiens@@yahoo.com R +@print{} Julie 555-6699 julie.perscrutabor@@skeeve.com F +@print{} Samuel 555-3430 samuel.lanceolis@@shu.edu A @end example @cindex actions, default @@ -2600,7 +2689,7 @@ action is to print all lines that match the pattern. @cindex actions, empty Thus, we could leave out the action (the @code{print} statement and the curly braces) in the previous example and the result would be the same: -@command{awk} prints all lines matching the pattern @samp{foo}. By comparison, +@command{awk} prints all lines matching the pattern @samp{li}. By comparison, omitting the @code{print} statement but retaining the curly braces makes an empty action that does nothing (i.e., no lines are printed). @@ -2745,29 +2834,23 @@ This program prints every line that contains the string strings, it is printed twice, once by each rule. This is what happens if we run this program on our two sample data files, -@file{BBS-list} and @file{inventory-shipped}: +@file{mail-list} and @file{inventory-shipped}: @example $ @kbd{awk '/12/ @{ print $0 @}} -> @kbd{/21/ @{ print $0 @}' BBS-list inventory-shipped} -@print{} aardvark 555-5553 1200/300 B -@print{} alpo-net 555-3412 2400/1200/300 A -@print{} barfly 555-7685 1200/300 A -@print{} bites 555-1675 2400/1200/300 A -@print{} core 555-2912 1200/300 C -@print{} fooey 555-1234 2400/1200/300 B -@print{} foot 555-6699 1200/300 B -@print{} macfoo 555-6480 1200/300 A -@print{} sdace 555-3430 2400/1200/300 A -@print{} sabafoo 555-2127 1200/300 C -@print{} sabafoo 555-2127 1200/300 C +> @kbd{/21/ @{ print $0 @}' mail-list inventory-shipped} +@print{} Anthony 555-3412 anthony.asserturo@@hotmail.com A +@print{} Camilla 555-2912 camilla.infusarum@@skynet.be R +@print{} Fabius 555-1234 fabius.undevicesimus@@ucb.edu F +@print{} Jean-Paul 555-2127 jeanpaul.campanorum@@nyu.edu R +@print{} Jean-Paul 555-2127 jeanpaul.campanorum@@nyu.edu R @print{} Jan 21 36 64 620 @print{} Apr 21 70 74 514 @end example @noindent -Note how the line beginning with @samp{sabafoo} -in @file{BBS-list} was printed twice, once for each rule. +Note how the line beginning with @samp{Jean-Paul} +in @file{mail-list} was printed twice, once for each rule. @node More Complex @section A More Complex Example @@ -2846,7 +2929,7 @@ separate rule, like this: @example awk '/12/ @{ print $0 @} - /21/ @{ print $0 @}' BBS-list inventory-shipped + /21/ @{ print $0 @}' mail-list inventory-shipped @end example @cindex @command{gawk}, newlines in @@ -2961,8 +3044,8 @@ noticed because it is ``hidden'' inside the comment. Thus, the @code{BEGIN} is noted as a syntax error. @cindex statements, multiple -@cindex @code{;} (semicolon) -@cindex semicolon (@code{;}) +@cindex @code{;} (semicolon), separating statements in actions +@cindex semicolon (@code{;}), separating statements in actions When @command{awk} statements within one rule are short, you might want to put more than one of them on a line. This is accomplished by separating the statements with a semicolon (@samp{;}). @@ -3022,6 +3105,7 @@ used once, and thrown away. Because @command{awk} programs are interpreted, you can avoid the (usually lengthy) compilation part of the typical edit-compile-test-debug cycle of software development. +@cindex Brian Kernighan's @command{awk} Complex programs have been written in @command{awk}, including a complete retargetable assembler for eight-bit microprocessors (@pxref{Glossary}, for more information), and a microcode assembler for a special-purpose Prolog @@ -3084,10 +3168,19 @@ There are two ways to run @command{awk}---with an explicit program or with one or more program files. Here are templates for both of them; items enclosed in [@dots{}] in these templates are optional: +@ifnotdocbook @example awk @r{[@var{options}]} -f progfile @r{[@code{--}]} @var{file} @dots{} awk @r{[@var{options}]} @r{[@code{--}]} '@var{program}' @var{file} @dots{} @end example +@end ifnotdocbook + +@c FIXME - find a better way to mark this up in docbook +@docbook +<screen>awk [<replaceable>options</replaceable>] -f progfile [<literal>--</literal>] <replaceable>file</replaceable> … +awk [<replaceable>options</replaceable>] [<literal>--</literal>] '<replaceable>program</replaceable>' <replaceable>file</replaceable> … +</screen> +@end docbook @cindex GNU long options @cindex long options @@ -3253,6 +3346,7 @@ Print the short version of the General Public License and then exit. @itemx --dump-variables@r{[}=@var{file}@r{]} @cindex @option{-d} option @cindex @option{--dump-variables} option +@cindex dump all variables of a program @cindex @file{awkvars.out} file @cindex files, @file{awkvars.out} @cindex variables, global, printing list of @@ -3406,7 +3500,7 @@ care to search for all occurrences of each inappropriate construct. As @cindex @option{--bignum} option Force arbitrary precision arithmetic on numbers. This option has no effect if @command{gawk} is not compiled to use the GNU MPFR and MP libraries -(@pxref{Arbitrary Precision Arithmetic}). +(@pxref{Gawk and MPFR}). @item -n @itemx --non-decimal-data @@ -3659,6 +3753,7 @@ file at all. @cindex @command{gawk}, @code{ARGIND} variable in @cindex @code{ARGIND} variable, command-line arguments +@cindex @code{ARGV} array, indexing into @cindex @code{ARGC}/@code{ARGV} variables, command-line arguments All these arguments are made available to your @command{awk} program in the @code{ARGV} array (@pxref{Built-in Variables}). Command-line options @@ -3669,6 +3764,7 @@ sets the variable @code{ARGIND} to the index in @code{ARGV} of the current element. @cindex input files, variable assignments and +@cindex variable assignments and input files The distinction between file name arguments and variable-assignment arguments is made when @command{awk} is about to open the next input file. At that point in execution, it checks the file name to see whether @@ -3746,6 +3842,7 @@ this file name itself.) @node Environment Variables @section The Environment Variables @command{gawk} Uses +@cindex environment variables used by @command{gawk} A number of environment variables influence how @command{gawk} behaves. @@ -3761,8 +3858,7 @@ behaves. @node AWKPATH Variable @subsection The @env{AWKPATH} Environment Variable @cindex @env{AWKPATH} environment variable -@cindex directories, searching -@cindex search paths +@cindex directories, searching for source files @cindex search paths, for source files @cindex differences in @command{awk} and @command{gawk}, @code{AWKPATH} environment variable @ifinfo @@ -3774,12 +3870,12 @@ implementations, you must supply a precise path name for each program file, unless the file is in the current directory. But in @command{gawk}, if the file name supplied to the @option{-f} or @option{-i} options -does not contain a @samp{/}, then @command{gawk} searches a list of +does not contain a directory separator @samp{/}, then @command{gawk} searches a list of directories (called the @dfn{search path}), one by one, looking for a file with the specified name. The search path is a string consisting of directory names -separated by colons. @command{gawk} gets its search path from the +separated by colons@footnote{Semicolons on MS-Windows and MS-DOS.}. @command{gawk} gets its search path from the @env{AWKPATH} environment variable. If that variable does not exist, @command{gawk} uses a default path, @samp{.:/usr/local/share/awk}.@footnote{Your version of @command{gawk} @@ -3837,8 +3933,7 @@ found, and @command{gawk} no longer needs to use @env{AWKPATH}. @node AWKLIBPATH Variable @subsection The @env{AWKLIBPATH} Environment Variable @cindex @env{AWKLIBPATH} environment variable -@cindex directories, searching -@cindex search paths +@cindex directories, searching for shared libraries @cindex search paths, for shared libraries @cindex differences in @command{awk} and @command{gawk}, @code{AWKLIBPATH} environment variable @@ -4123,7 +4218,6 @@ they will @emph{not} be in the next release). @c update this section for each release! -@cindex @code{PROCINFO} array The process-related special files @file{/dev/pid}, @file{/dev/ppid}, @file{/dev/pgrpid}, and @file{/dev/user} were deprecated in @command{gawk} 3.1, but still worked. As of version 4.0, they are no longer @@ -4149,6 +4243,7 @@ in case some option becomes obsolete in a future version of @command{gawk}. @author Obi-Wan @end quotation +@cindex shells, sea This @value{SECTION} intentionally left blank. @@ -4161,7 +4256,7 @@ blank. @table @code @item -W nostalgia @itemx --nostalgia -Print the message @code{"awk: bailing out near line 1"} and dump core. +Print the message @samp{awk: bailing out near line 1} and dump core. This option was inspired by the common behavior of very early versions of Unix @command{awk} and by a t--shirt. The message is @emph{not} subject to translation in non-English locales. @@ -4207,7 +4302,7 @@ long-undocumented ``feature'' of Unix @code{awk}. @node Regexp @chapter Regular Expressions -@cindex regexp, See regular expressions +@cindex regexp @c STARTOFRANGE regexp @cindex regular expressions @@ -4216,8 +4311,8 @@ set of strings. Because regular expressions are such a fundamental part of @command{awk} programming, their format and use deserve a separate @value{CHAPTER}. -@cindex forward slash (@code{/}) -@cindex @code{/} (forward slash) +@cindex forward slash (@code{/}) to enclose regular expressions +@cindex @code{/} (forward slash) to enclose regular expressions A regular expression enclosed in slashes (@samp{/}) is an @command{awk} pattern that matches every input record whose text belongs to that set. @@ -4254,14 +4349,14 @@ slashes. Then the regular expression is tested against the entire text of each record. (Normally, it only needs to match some part of the text in order to succeed.) For example, the following prints the second field of each record that contains the string -@samp{foo} anywhere in it: +@samp{li} anywhere in it: @example -$ @kbd{awk '/foo/ @{ print $2 @}' BBS-list} -@print{} 555-1234 +$ @kbd{awk '/li/ @{ print $2 @}' mail-list} +@print{} 555-5553 +@print{} 555-0542 @print{} 555-6699 -@print{} 555-6480 -@print{} 555-2127 +@print{} 555-3430 @end example @cindex regular expressions, operators @@ -4273,9 +4368,9 @@ $ @kbd{awk '/foo/ @{ print $2 @}' BBS-list} @cindex @code{!} (exclamation point), @code{!~} operator @cindex exclamation point (@code{!}), @code{!~} operator @c @cindex operators, @code{!~} -@cindex @code{if} statement -@cindex @code{while} statement -@cindex @code{do}-@code{while} statement +@cindex @code{if} statement, use of regexps in +@cindex @code{while} statement, use of regexps in +@cindex @code{do}-@code{while} statement, use of regexps in @c @cindex statements, @code{if} @c @cindex statements, @code{while} @c @cindex statements, @code{do} @@ -4334,6 +4429,7 @@ $ @kbd{awk '$1 !~ /J/' inventory-shipped} @end example @cindex regexp constants +@cindex constant regexps @cindex regular expressions, constants, See regexp constants When a regexp is enclosed in slashes, such as @code{/foo/}, we call it a @dfn{regexp constant}, much like @code{5.27} is a numeric constant and @@ -4342,7 +4438,7 @@ a @dfn{regexp constant}, much like @code{5.27} is a numeric constant and @node Escape Sequences @section Escape Sequences -@cindex escape sequences +@cindex escape sequences, in strings @cindex backslash (@code{\}), in escape sequences @cindex @code{\} (backslash), in escape sequences Some characters cannot be included literally in string constants @@ -4507,6 +4603,7 @@ leaves what happens as undefined. There are two choices: @c @cindex automatic warnings @c @cindex warnings, automatic +@cindex Brian Kernighan's @command{awk} @table @asis @item Strip the backslash out This is what Brian Kernighan's @command{awk} and @command{gawk} both do. @@ -4520,6 +4617,7 @@ two backslashes in the string: @samp{FS = @w{"[ \t]+\\|[ \t]+"}}.) @cindex @command{gawk}, escape sequences @cindex Unix @command{awk}, backslashes in escape sequences +@cindex @command{mawk} utility @item Leave the backslash alone Some other @command{awk} implementations do this. In such implementations, typing @code{"a\qc"} is the same as typing @@ -4551,6 +4649,7 @@ escape sequences literally when used in regexp constants. Thus, @section Regular Expression Operators @c STARTOFRANGE regexpo @cindex regular expressions, operators +@cindex metacharacters in regular expressions You can combine regular expressions with special characters, called @dfn{regular expression operators} or @dfn{metacharacters}, to @@ -4569,8 +4668,8 @@ Here is a list of metacharacters. All characters that are not escape sequences and that are not listed in the table stand for themselves: @table @code -@cindex backslash (@code{\}) -@cindex @code{\} (backslash) +@cindex backslash (@code{\}), regexp operator +@cindex @code{\} (backslash), regexp operator @item \ This is used to suppress the special meaning of a character when matching. For example, @samp{\$} @@ -4595,8 +4694,8 @@ The condition is not true in the following example: if ("line1\nLINE 2" ~ /^L/) @dots{} @end example -@cindex @code{$} (dollar sign) -@cindex dollar sign (@code{$}) +@cindex @code{$} (dollar sign), regexp operator +@cindex dollar sign (@code{$}), regexp operator @item $ This is similar to @samp{^}, but it matches only at the end of a string. For example, @samp{p$} @@ -4608,8 +4707,8 @@ The condition in the following example is not true: if ("line1\nLINE 2" ~ /1$/) @dots{} @end example -@cindex @code{.} (period) -@cindex period (@code{.}) +@cindex @code{.} (period), regexp operator +@cindex period (@code{.}), regexp operator @item . @r{(period)} This matches any single character, @emph{including} the newline character. For example, @samp{.P} @@ -4625,11 +4724,12 @@ character, which is a character with all bits equal to zero. Otherwise, @sc{nul} is just another character. Other versions of @command{awk} may not be able to match the @sc{nul} character. -@cindex @code{[]} (square brackets) -@cindex square brackets (@code{[]}) +@cindex @code{[]} (square brackets), regexp operator +@cindex square brackets (@code{[]}), regexp operator @cindex bracket expressions @cindex character sets, See Also bracket expressions @cindex character lists, See bracket expressions +@cindex character classes, See bracket expressions @item [@dots{}] This is called a @dfn{bracket expression}.@footnote{In other literature, you may see a bracket expression referred to as either a @@ -4662,8 +4762,8 @@ means it matches any string that starts with @samp{P} or contains a digit. The alternation applies to the largest possible regexps on either side. -@cindex @code{()} (parentheses) -@cindex parentheses @code{()} +@cindex @code{()} (parentheses), regexp operator +@cindex parentheses @code{()}, regexp operator @item (@dots{}) Parentheses are used for grouping in regular expressions, as in arithmetic. They can be used to concatenate regular expressions @@ -4691,8 +4791,8 @@ prints every record in @file{sample} containing a string of the form Notice the escaping of the parentheses by preceding them with backslashes. -@cindex @code{+} (plus sign) -@cindex plus sign (@code{+}) +@cindex @code{+} (plus sign), regexp operator +@cindex plus sign (@code{+}), regexp operator @item + This symbol is similar to @samp{*}, except that the preceding expression must be matched at least once. This means that @samp{wh+y} @@ -4705,14 +4805,14 @@ way of writing the last @samp{*} example: awk '/\(c[ad]+r x\)/ @{ print @}' sample @end example -@cindex @code{?} (question mark) regexp operator -@cindex question mark (@code{?}) regexp operator +@cindex @code{?} (question mark), regexp operator +@cindex question mark (@code{?}), regexp operator @item ? This symbol is similar to @samp{*}, except that the preceding expression can be matched either once or not at all. For example, @samp{fe?d} matches @samp{fed} and @samp{fd}, but nothing else. -@cindex interval expressions +@cindex interval expressions, regexp operator @item @{@var{n}@} @itemx @{@var{n},@} @itemx @{@var{n},@var{m}@} @@ -4789,6 +4889,7 @@ expressions are not available in regular expressions. @cindex bracket expressions @cindex bracket expressions, range expressions @cindex range expressions (regexps) +@cindex character lists in regular expression As mentioned earlier, a bracket expression matches any character amongst those listed between the opening and closing square brackets. @@ -5028,10 +5129,10 @@ Matches the empty string at the end of a buffer (string). @end table -@cindex @code{^} (caret) -@cindex caret (@code{^}) -@cindex @code{?} (question mark) regexp operator -@cindex question mark (@code{?}) regexp operator +@cindex @code{^} (caret), regexp operator +@cindex caret (@code{^}), regexp operator +@cindex @code{?} (question mark), regexp operator +@cindex question mark (@code{?}), regexp operator Because @samp{^} and @samp{$} always work in terms of the beginning and end of strings, these operators don't add any new capabilities for @command{awk}. They are provided for compatibility with other @@ -5052,7 +5153,7 @@ lesser of two evils. @c @c Should really do this with file inclusion. @cindex regular expressions, @command{gawk}, command-line options -@cindex @command{gawk}, command-line options +@cindex @command{gawk}, command-line options, and regular expressions The various command-line options (@pxref{Options}) control how @command{gawk} interprets characters in regexps: @@ -5075,6 +5176,7 @@ Only POSIX regexps are supported; the GNU operators are not special (e.g., @samp{\w} matches a literal @samp{w}). Interval expressions are allowed. +@cindex Brian Kernighan's @command{awk} @item @code{--traditional} Traditional Unix @command{awk} regexps are matched. The GNU operators are not special, and interval expressions are not available. @@ -5130,7 +5232,7 @@ This works in any POSIX-compliant @command{awk}. @cindex tilde (@code{~}), @code{~} operator @cindex @code{!} (exclamation point), @code{!~} operator @cindex exclamation point (@code{!}), @code{!~} operator -@cindex @code{IGNORECASE} variable +@cindex @code{IGNORECASE} variable, with @code{~} and @code{!~} operators @cindex @command{gawk}, @code{IGNORECASE} variable in @c @cindex variables, @code{IGNORECASE} Another method, specific to @command{gawk}, is to set the variable @@ -5351,6 +5453,7 @@ occur often in practice, but it's worth noting for future reference. @chapter Reading Input Files @c STARTOFRANGE infir +@cindex reading input files @cindex input files, reading @cindex input files @cindex @code{FILENAME} variable @@ -5437,68 +5540,79 @@ To do this, use the special @code{BEGIN} pattern (@pxref{BEGIN/END}). For example: -@cindex @code{BEGIN} pattern @example -awk 'BEGIN @{ RS = "/" @} - @{ print $0 @}' BBS-list +awk 'BEGIN @{ RS = "u" @} + @{ print $0 @}' mail-list @end example @noindent -changes the value of @code{RS} to @code{"/"}, before reading any input. -This is a string whose first character is a slash; as a result, records -are separated by slashes. Then the input file is read, and the second +changes the value of @code{RS} to @samp{u}, before reading any input. +This is a string whose first character is the letter ``u;'' as a result, records +are separated by the letter ``u.'' Then the input file is read, and the second rule in the @command{awk} program (the action with no pattern) prints each record. Because each @code{print} statement adds a newline at the end of its output, this @command{awk} program copies the input -with each slash changed to a newline. Here are the results of running -the program on @file{BBS-list}: - -@example -$ @kbd{awk 'BEGIN @{ RS = "/" @}} -> @kbd{@{ print $0 @}' BBS-list} -@print{} aardvark 555-5553 1200 -@print{} 300 B -@print{} alpo-net 555-3412 2400 -@print{} 1200 -@print{} 300 A -@print{} barfly 555-7685 1200 -@print{} 300 A -@print{} bites 555-1675 2400 -@print{} 1200 -@print{} 300 A -@print{} camelot 555-0542 300 C -@print{} core 555-2912 1200 -@print{} 300 C -@print{} fooey 555-1234 2400 -@print{} 1200 -@print{} 300 B -@print{} foot 555-6699 1200 -@print{} 300 B -@print{} macfoo 555-6480 1200 -@print{} 300 A -@print{} sdace 555-3430 2400 -@print{} 1200 -@print{} 300 A -@print{} sabafoo 555-2127 1200 -@print{} 300 C -@print{} +with each @samp{u} changed to a newline. Here are the results of running +the program on @file{mail-list}: + +@example +$ @kbd{awk 'BEGIN @{ RS = "u" @}} +> @kbd{@{ print $0 @}' mail-list} +@print{} Amelia 555-5553 amelia.zodiac +@print{} sq +@print{} e@@gmail.com F +@print{} Anthony 555-3412 anthony.assert +@print{} ro@@hotmail.com A +@print{} Becky 555-7685 becky.algebrar +@print{} m@@gmail.com A +@print{} Bill 555-1675 bill.drowning@@hotmail.com A +@print{} Broderick 555-0542 broderick.aliq +@print{} otiens@@yahoo.com R +@print{} Camilla 555-2912 camilla.inf +@print{} sar +@print{} m@@skynet.be R +@print{} Fabi +@print{} s 555-1234 fabi +@print{} s. +@print{} ndevicesim +@print{} s@@ +@print{} cb.ed +@print{} F +@print{} J +@print{} lie 555-6699 j +@print{} lie.perscr +@print{} tabor@@skeeve.com F +@print{} Martin 555-6480 martin.codicib +@print{} s@@hotmail.com A +@print{} Sam +@print{} el 555-3430 sam +@print{} el.lanceolis@@sh +@print{} .ed +@print{} A +@print{} Jean-Pa +@print{} l 555-2127 jeanpa +@print{} l.campanor +@print{} m@@ny +@print{} .ed +@print{} R +@print{} @end example @noindent -Note that the entry for the @samp{camelot} BBS is not split. +Note that the entry for the name @samp{Bill} is not split. In the original data file (@pxref{Sample Data Files}), the line looks like this: @example -camelot 555-0542 300 C +Bill 555-1675 bill.drowning@@hotmail.com A @end example @noindent -It has one baud rate only, so there are no slashes in the record, -unlike the others which have two or more baud rates. -In fact, this record is treated as part of the record -for the @samp{core} BBS; the newline separating them in the output +It contains no @samp{u} so there is no reason to split the record, +unlike the others which have one or more occurrences of the @samp{u}. +In fact, this record is treated as part of the previous record; +the newline separating them in the output is the original newline in the data file, not the one added by @command{awk} when it printed the record! @@ -5509,14 +5623,17 @@ using the variable-assignment feature (@pxref{Other Arguments}): @example -awk '@{ print $0 @}' RS="/" BBS-list +awk '@{ print $0 @}' RS="u" mail-list @end example @noindent -This sets @code{RS} to @samp{/} before processing @file{BBS-list}. +This sets @code{RS} to @samp{u} before processing @file{mail-list}. -Using an unusual character such as @samp{/} for the record separator -produces correct behavior in the vast majority of cases. +Using an alphabetic character such as @samp{u} for the record separator +is highly likely to produce strange results. +Using an unusual character such as @samp{/} is more likely to +produce correct behavior in the majority of cases, but there +are no guarantees. The moral is: Know Your Data. There is one unusual case, that occurs when @command{gawk} is being fully POSIX-compliant (@pxref{Options}). @@ -5538,6 +5655,7 @@ Reaching the end of an input file terminates the current input record, even if the last character in the file is not the character in @code{RS}. @value{DARKCORNER} +@cindex empty strings @cindex null strings @cindex strings, empty, See null strings The empty string @code{""} (a string without any characters) @@ -5669,7 +5787,7 @@ character as a record separator. However, this is a special case: @command{mawk} does not allow embedded @sc{nul} characters in strings. @cindex records, treating files as -@cindex files, as single records +@cindex treating files, as single records The best way to treat a whole file as a single record is to simply read the file in, one record at a time, concatenating each record onto the end of the previous ones. @@ -5746,31 +5864,29 @@ when you are not interested in specific fields. Here are some more examples: @example -$ @kbd{awk '$1 ~ /foo/ @{ print $0 @}' BBS-list} -@print{} fooey 555-1234 2400/1200/300 B -@print{} foot 555-6699 1200/300 B -@print{} macfoo 555-6480 1200/300 A -@print{} sabafoo 555-2127 1200/300 C +$ @kbd{awk '$1 ~ /li/ @{ print $0 @}' mail-list} +@print{} Amelia 555-5553 amelia.zodiacusque@@gmail.com F +@print{} Julie 555-6699 julie.perscrutabor@@skeeve.com F @end example @noindent -This example prints each record in the file @file{BBS-list} whose first -field contains the string @samp{foo}. The operator @samp{~} is called a +This example prints each record in the file @file{mail-list} whose first +field contains the string @samp{li}. The operator @samp{~} is called a @dfn{matching operator} (@pxref{Regexp Usage}); it tests whether a string (here, the field @code{$1}) matches a given regular expression. By contrast, the following example -looks for @samp{foo} in @emph{the entire record} and prints the first +looks for @samp{li} in @emph{the entire record} and prints the first field and the last field for each matching input record: @example -$ @kbd{awk '/foo/ @{ print $1, $NF @}' BBS-list} -@print{} fooey B -@print{} foot B -@print{} macfoo A -@print{} sabafoo C +$ @kbd{awk '/li/ @{ print $1, $NF @}' mail-list} +@print{} Amelia F +@print{} Broderick R +@print{} Julie F +@print{} Samuel A @end example @c ENDOFRANGE fiex @@ -5798,7 +5914,7 @@ the record has fewer than 20 fields, so this prints a blank line. Here is another example of using expressions as field numbers: @example -awk '@{ print $(2*2) @}' BBS-list +awk '@{ print $(2*2) @}' mail-list @end example @command{awk} evaluates the expression @samp{(2*2)} and uses @@ -5807,8 +5923,8 @@ represents multiplication, so the expression @samp{2*2} evaluates to four. The parentheses are used so that the multiplication is done before the @samp{$} operation; they are necessary whenever there is a binary operator in the field-number expression. This example, then, prints the -hours of operation (the fourth field) for every line of the file -@file{BBS-list}. (All of the @command{awk} operators are listed, in +type of relationship (the fourth field) for every line of the file +@file{mail-list}. (All of the @command{awk} operators are listed, in order of decreasing precedence, in @ref{Precedence}.) @@ -6219,7 +6335,7 @@ was ignored when finding @code{$1}, it is not part of the new @code{$0}. Finally, the last @code{print} statement prints the new @code{$0}. @cindex @code{FS}, containing @code{^} -@cindex @code{^}, in @code{FS} +@cindex @code{^} (caret), in @code{FS} @cindex dark corner, @code{^}, in @code{FS} There is an additional subtlety to be aware of when using regular expressions for field splitting. @@ -6230,6 +6346,7 @@ different @command{awk} versions answer this question differently, and you should not rely on any specific behavior in your programs. @value{DARKCORNER} +@cindex Brian Kernighan's @command{awk} As a point of information, Brian Kernighan's @command{awk} allows @samp{^} to match only at the beginning of the record. @command{gawk} also works this way. For example: @@ -6273,7 +6390,7 @@ $ @kbd{echo a b | gawk 'BEGIN @{ FS = "" @}} @end example @cindex dark corner, @code{FS} as null string -@cindex FS variable, as null string +@cindex @code{FS} variable, as null string Traditionally, the behavior of @code{FS} equal to @code{""} was not defined. In this case, most versions of Unix @command{awk} simply treat the entire record as only having one field. @@ -6285,10 +6402,8 @@ behaves this way. @node Command Line Field Separator @subsection Setting @code{FS} from the Command Line -@cindex @option{-F} option -@cindex options, command-line -@cindex command line, options -@cindex field separators, on command line +@cindex @option{-F} option, command line +@cindex field separator, on command line @cindex command line, @code{FS} on@comma{} setting @cindex @code{FS} variable, setting from command line @@ -6338,66 +6453,59 @@ figures that you really want your fields to be separated with TABs and not @samp{t}s. Use @samp{-v FS="t"} or @samp{-F"[t]"} on the command line if you really do want to separate your fields with @samp{t}s. -As an example, let's use an @command{awk} program file called @file{baud.awk} -that contains the pattern @code{/300/} and the action @samp{print $1}: +As an example, let's use an @command{awk} program file called @file{edu.awk} +that contains the pattern @code{/edu/} and the action @samp{print $1}: @example -/300/ @{ print $1 @} +/edu/ @{ print $1 @} @end example Let's also set @code{FS} to be the @samp{-} character and run the -program on the file @file{BBS-list}. The following command prints a -list of the names of the bulletin boards that operate at 300 baud and +program on the file @file{mail-list}. The following command prints a +list of the names of the people that work at or attend a university, and the first three digits of their phone numbers: @c tweaked to make the tex output look better in @smallbook @example -$ @kbd{awk -F- -f baud.awk BBS-list} -@print{} aardvark 555 -@print{} alpo -@print{} barfly 555 -@print{} bites 555 -@print{} camelot 555 -@print{} core 555 -@print{} fooey 555 -@print{} foot 555 -@print{} macfoo 555 -@print{} sdace 555 -@print{} sabafoo 555 +$ @kbd{awk -F- -f edu.awk mail-list} +@print{} Fabius 555 +@print{} Samuel 555 +@print{} Jean @end example @noindent -Note the second line of output. The second line +Note the third line of output. The third line in the original file looked like this: @example -alpo-net 555-3412 2400/1200/300 A +Jean-Paul 555-2127 jeanpaul.campanorum@@nyu.edu R @end example -The @samp{-} as part of the system's name was used as the field +The @samp{-} as part of the person's name was used as the field separator, instead of the @samp{-} in the phone number that was originally intended. This demonstrates why you have to be careful in choosing your field and record separators. @cindex Unix @command{awk}, password files@comma{} field separators and -Perhaps the most common use of a single character as the field -separator occurs when processing the Unix system password file. -On many Unix systems, each user has a separate entry in the system password -file, one line per user. The information in these lines is separated -by colons. The first field is the user's login name and the second is -the user's (encrypted or shadow) password. A password file entry might look -like this: +Perhaps the most common use of a single character as the field separator +occurs when processing the Unix system password file. On many Unix +systems, each user has a separate entry in the system password file, one +line per user. The information in these lines is separated by colons. +The first field is the user's login name and the second is the user's +encrypted or shadow password. (A shadow password is indicated by the +presence of a single @samp{x} in the second field.) A password file +entry might look like this: @cindex Robbins, Arnold @example -arnold:xyzzy:2076:10:Arnold Robbins:/home/arnold:/bin/bash +arnold:x:2076:10:Arnold Robbins:/home/arnold:/bin/bash @end example The following program searches the system password file and prints -the entries for users who have no password: +the entries for users whose full name is not indicated: @example -awk -F: '$2 == ""' /etc/passwd +awk -F: '$5 == ""' /etc/passwd @end example @node Full Line Fields @@ -6455,7 +6563,7 @@ POSIX standard.) @sidebar Changing @code{FS} Does Not Affect the Fields @cindex POSIX @command{awk}, field separators and -@cindex field separators, POSIX and +@cindex field separator, POSIX and According to the POSIX standard, @command{awk} is supposed to behave as if each record is split into fields at the time it is read. In particular, this means that if you change the value of @code{FS} @@ -6778,6 +6886,7 @@ available for splitting regular strings (@pxref{String Functions}). @node Multiple Line @section Multiple-Line Records +@cindex multiple-line records @c STARTOFRANGE recm @cindex records, multiline @c STARTOFRANGE imr @@ -6829,7 +6938,8 @@ after the last record, the final newline is removed from the record. In the second case, this special processing is not done. @value{DARKCORNER} -@cindex field separators, in multiline records +@cindex field separator, in multiline records +@cindex @code{FS}, in multiline records Now that the input is separated into records, the second step is to separate the fields in the record. One way to do this is to divide each of the lines into fields in the normal manner. This happens by default @@ -6977,7 +7087,7 @@ and study the @code{getline} command @emph{after} you have reviewed the rest of this @value{DOCUMENT} and have a good knowledge of how @command{awk} works. @cindex @command{gawk}, @code{ERRNO} variable in -@cindex @code{ERRNO} variable +@cindex @code{ERRNO} variable, with @command{getline} command @cindex differences in @command{awk} and @command{gawk}, @code{getline} command @cindex @code{getline} command, return values @cindex @option{--sandbox} option, input redirection with @code{getline} @@ -7073,6 +7183,7 @@ rule in the program. @xref{Next Statement}. @node Getline/Variable @subsection Using @code{getline} into a Variable +@cindex @code{getline} into a variable @cindex variables, @code{getline} command into@comma{} using You can use @samp{getline @var{var}} to read the next record from @@ -7124,6 +7235,7 @@ the value of @code{NF} do not change. @node Getline/File @subsection Using @code{getline} from a File +@cindex @code{getline} from a file @cindex input redirection @cindex redirection of input @cindex @code{<} (left angle bracket), @code{<} operator (I/O) @@ -7172,8 +7284,6 @@ from the file @var{file}, and put it in the variable @var{var}. As above, @var{file} is a string-valued expression that specifies the file from which to read. -@cindex @command{gawk}, @code{RT} variable in -@cindex @code{RT} variable In this version of @code{getline}, none of the built-in variables are changed and the record is not split into fields. The only variable changed is @var{var}.@footnote{This is not quite true. @code{RT} could @@ -7198,7 +7308,6 @@ Note here how the name of the extra input file is not built into the program; it is taken directly from the data, specifically from the second field on the @samp{@@include} line. -@cindex @code{close()} function The @code{close()} function is called to ensure that if two identical @samp{@@include} lines appear in the input, the entire specified file is included twice. @@ -7215,6 +7324,7 @@ that does handle nested @samp{@@include} statements. @subsection Using @code{getline} from a Pipe @c From private email, dated October 2, 1988. Used by permission, March 2013. +@cindex Kernighan, Brian @quotation @i{Omniscience has much to recommend it. Failing that, attention to details would be useful.} @@ -7224,7 +7334,7 @@ Failing that, attention to details would be useful.} @cindex @code{|} (vertical bar), @code{|} operator (I/O) @cindex vertical bar (@code{|}), @code{|} operator (I/O) @cindex input pipeline -@cindex pipes, input +@cindex pipe, input @cindex operators, input/output The output of a command can also be piped into @code{getline}, using @samp{@var{command} | getline}. In @@ -7248,7 +7358,6 @@ produced by running the rest of the line as a shell command: @end example @noindent -@cindex @code{close()} function The @code{close()} function is called to ensure that if two identical @samp{@@execute} lines appear in the input, the command is run for each one. @@ -7302,6 +7411,8 @@ because the concatenation operator is not parenthesized. You should write it as @samp{(@w{"echo "} "date") | getline} if you want your program to be portable to all @command{awk} implementations. +@cindex Brian Kernighan's @command{awk} +@cindex @command{mawk} utility @quotation NOTE Unfortunately, @command{gawk} has not been consistent in its treatment of a construct like @samp{@w{"echo "} "date" | getline}. @@ -7626,6 +7737,7 @@ indefinitely until some other process opens it for writing. @node Command line directories @section Directories On The Command Line +@cindex differences in @command{awk} and @command{gawk}, command line directories @cindex directories, command line @cindex command line, directories on @@ -7869,13 +7981,29 @@ program by using a new value of @code{OFS}. @example $ @kbd{awk 'BEGIN @{ OFS = ";"; ORS = "\n\n" @}} -> @kbd{@{ print $1, $2 @}' BBS-list} -@print{} aardvark;555-5553 -@print{} -@print{} alpo-net;555-3412 -@print{} -@print{} barfly;555-7685 -@dots{} +> @kbd{@{ print $1, $2 @}' mail-list} +@print{} Amelia;555-5553 +@print{} +@print{} Anthony;555-3412 +@print{} +@print{} Becky;555-7685 +@print{} +@print{} Bill;555-1675 +@print{} +@print{} Broderick;555-0542 +@print{} +@print{} Camilla;555-2912 +@print{} +@print{} Fabius;555-1234 +@print{} +@print{} Julie;555-6699 +@print{} +@print{} Martin;555-6480 +@print{} +@print{} Samuel;555-3430 +@print{} +@print{} Jean-Paul;555-2127 +@print{} @end example If the value of @code{ORS} does not contain a newline, the program's output @@ -7897,7 +8025,7 @@ numbers can be formatted. The different format specifications are discussed more fully in @ref{Control Letters}. -@cindex @code{sprintf()} function +@cindexawkfunc{sprintf} @cindex @code{OFMT} variable @cindex output, format specifier@comma{} @code{OFMT} The built-in variable @code{OFMT} contains the default format specification @@ -7963,7 +8091,7 @@ parentheses are necessary if any of the item expressions use the @samp{>} relational operator; otherwise, it can be confused with an output redirection (@pxref{Redirection}). -@cindex format strings +@cindex format specifiers The difference between @code{printf} and @code{print} is the @var{format} argument. This is an expression whose value is taken as a string; it specifies how to output each of the other arguments. It is called the @@ -8349,30 +8477,30 @@ The following simple example shows how to use @code{printf} to make an aligned table: @example -awk '@{ printf "%-10s %s\n", $1, $2 @}' BBS-list +awk '@{ printf "%-10s %s\n", $1, $2 @}' mail-list @end example @noindent This command -prints the names of the bulletin boards (@code{$1}) in the file -@file{BBS-list} as a string of 10 characters that are left-justified. It also +prints the names of the people (@code{$1}) in the file +@file{mail-list} as a string of 10 characters that are left-justified. It also prints the phone numbers (@code{$2}) next on the line. This produces an aligned two-column table of names and phone numbers, as shown here: @example -$ @kbd{awk '@{ printf "%-10s %s\n", $1, $2 @}' BBS-list} -@print{} aardvark 555-5553 -@print{} alpo-net 555-3412 -@print{} barfly 555-7685 -@print{} bites 555-1675 -@print{} camelot 555-0542 -@print{} core 555-2912 -@print{} fooey 555-1234 -@print{} foot 555-6699 -@print{} macfoo 555-6480 -@print{} sdace 555-3430 -@print{} sabafoo 555-2127 +$ @kbd{awk '@{ printf "%-10s %s\n", $1, $2 @}' mail-list} +@print{} Amelia 555-5553 +@print{} Anthony 555-3412 +@print{} Becky 555-7685 +@print{} Bill 555-1675 +@print{} Broderick 555-0542 +@print{} Camilla 555-2912 +@print{} Fabius 555-1234 +@print{} Julie 555-6699 +@print{} Martin 555-6480 +@print{} Samuel 555-3430 +@print{} Jean-Paul 555-2127 @end example In this case, the phone numbers had to be printed as strings because @@ -8393,7 +8521,7 @@ the @command{awk} program: @example awk 'BEGIN @{ print "Name Number" print "---- ------" @} - @{ printf "%-10s %s\n", $1, $2 @}' BBS-list + @{ printf "%-10s %s\n", $1, $2 @}' mail-list @end example The above example mixes @code{print} and @code{printf} statements in @@ -8403,7 +8531,7 @@ same results: @example awk 'BEGIN @{ printf "%-10s %s\n", "Name", "Number" printf "%-10s %s\n", "----", "------" @} - @{ printf "%-10s %s\n", $1, $2 @}' BBS-list + @{ printf "%-10s %s\n", $1, $2 @}' mail-list @end example @noindent @@ -8418,7 +8546,7 @@ emphasized by storing it in a variable, like this: awk 'BEGIN @{ format = "%-10s %s\n" printf format, "Name", "Number" printf format, "----", "------" @} - @{ printf format, $1, $2 @}' BBS-list + @{ printf format, $1, $2 @}' mail-list @end example @c !!! exercise @@ -8475,20 +8603,20 @@ before the first output is written to it. Subsequent writes to the same @var{output-file} do not erase @var{output-file}, but append to it. (This is different from how you use redirections in shell scripts.) If @var{output-file} does not exist, it is created. For example, here -is how an @command{awk} program can write a list of BBS names to one +is how an @command{awk} program can write a list of peoples' names to one file named @file{name-list}, and a list of phone numbers to another file named @file{phone-list}: @example $ @kbd{awk '@{ print $2 > "phone-list"} -> @kbd{print $1 > "name-list" @}' BBS-list} +> @kbd{print $1 > "name-list" @}' mail-list} $ @kbd{cat phone-list} @print{} 555-5553 @print{} 555-3412 @dots{} $ @kbd{cat name-list} -@print{} aardvark -@print{} alpo-net +@print{} Amelia +@print{} Anthony @dots{} @end example @@ -8506,7 +8634,7 @@ appended to the file. If @var{output-file} does not exist, then it is created. @cindex @code{|} (vertical bar), @code{|} operator (I/O) -@cindex pipes, output +@cindex pipe, output @cindex output, pipes @item print @var{items} | @var{command} It is possible to send output to another program through a pipe @@ -8517,7 +8645,7 @@ to another process created to execute @var{command}. The redirection argument @var{command} is actually an @command{awk} expression. Its value is converted to a string whose contents give the shell command to be run. For example, the following produces two -files, one unsorted list of BBS names, and one list sorted in reverse +files, one unsorted list of peoples' names, and one list sorted in reverse alphabetical order: @ignore @@ -8530,7 +8658,7 @@ alone for now and let's hope no-one notices. @example awk '@{ print $1 > "names.unsorted" command = "sort -r > names.sorted" - print $1 | command @}' BBS-list + print $1 | command @}' mail-list @end example The unsorted list is written with an ordinary redirection, while @@ -8740,9 +8868,9 @@ has been ported to, not just those that are POSIX-compliant: @cindex extensions, common@comma{} @code{/dev/stdout} special file @cindex extensions, common@comma{} @code{/dev/stderr} special file @cindex file names, standard streams in @command{gawk} -@cindex @code{/dev/@dots{}} special files (@command{gawk}) +@cindex @code{/dev/@dots{}} special files @cindex files, @code{/dev/@dots{}} special files -@cindex @code{/dev/fd/@var{N}} special files +@cindex @code{/dev/fd/@var{N}} special files (@command{gawk}) @table @file @item /dev/stdin The standard input (file descriptor 0). @@ -8843,7 +8971,7 @@ Doing so results in unpredictable behavior. @c STARTOFRANGE ofc @cindex output, files@comma{} closing @c STARTOFRANGE pc -@cindex pipes, closing +@cindex pipe, closing @c STARTOFRANGE cc @cindex coprocesses, closing @cindex @code{getline} command, coprocesses@comma{} using from @@ -8861,7 +8989,7 @@ the file name or command associated with it, and subsequent writes to the same file or command are appended to the previous writes. The file or pipe stays open until @command{awk} exits. -@cindex @code{close()} function +@cindexawkfunc{close} This implies that special steps are necessary in order to read the same file again from the beginning, or to rerun a shell command (rather than reading more output from the same command). The @code{close()} function @@ -8946,6 +9074,7 @@ a separate message. @cindex differences in @command{awk} and @command{gawk}, @code{close()} function @cindex portability, @code{close()} function and +@cindex @code{close()} function, portability If you use more files than the system allows you to have open, @command{gawk} attempts to multiplex the available open files among your data files. @command{gawk}'s ability to do this depends upon the @@ -9025,7 +9154,7 @@ retval = close(command) # syntax error in many Unix awks @end example @cindex @command{gawk}, @code{ERRNO} variable in -@cindex @code{ERRNO} variable +@cindex @code{ERRNO} variable, with @command{close()} function @command{gawk} treats @code{close()} as a function. The return value is @minus{}1 if the argument names something that was never opened with a redirection, or if there is @@ -9124,7 +9253,8 @@ have different forms, but are stored identically internally. @node Scalar Constants @subsubsection Numeric and String Constants -@cindex numeric, constants +@cindex constants, numeric +@cindex numeric constants A @dfn{numeric constant} stands for a number. This number can be an integer, a decimal fraction, or a number in scientific (exponential) notation.@footnote{The internal representation of all numbers, @@ -9150,7 +9280,7 @@ double-quotation marks. For example: @noindent @cindex differences in @command{awk} and @command{gawk}, strings -@cindex strings, length of +@cindex strings, length limitations represents the string whose contents are @samp{parrot}. Strings in @command{gawk} can be of any length, and they can contain any of the possible eight-bit ASCII characters including ASCII @sc{nul} (character code zero). @@ -9337,9 +9467,9 @@ upon the contents of the current input record. @cindex differences in @command{awk} and @command{gawk}, regexp constants @cindex dark corner, regexp constants, as arguments to user-defined functions -@cindex @code{gensub()} function (@command{gawk}) -@cindex @code{sub()} function -@cindex @code{gsub()} function +@cindexgawkfunc{gensub} +@cindexawkfunc{sub} +@cindexawkfunc{gsub} Constant regular expressions are also used as the first argument for the @code{gensub()}, @code{sub()}, and @code{gsub()} functions, as the second argument of the @code{match()} function, @@ -9472,7 +9602,7 @@ its position among the input file arguments---after the processing of the preceding input file argument. For example: @example -awk '@{ print $n @}' n=4 inventory-shipped n=2 BBS-list +awk '@{ print $n @}' n=4 inventory-shipped n=2 mail-list @end example @noindent @@ -9481,10 +9611,10 @@ the first file is read, the command line sets the variable @code{n} equal to four. This causes the fourth field to be printed in lines from @file{inventory-shipped}. After the first file has finished, but before the second file is started, @code{n} is set to two, so that the -second field is printed in lines from @file{BBS-list}: +second field is printed in lines from @file{mail-list}: @example -$ @kbd{awk '@{ print $n @}' n=4 inventory-shipped n=2 BBS-list} +$ @kbd{awk '@{ print $n @}' n=4 inventory-shipped n=2 mail-list} @print{} 15 @print{} 24 @dots{} @@ -9807,9 +9937,9 @@ specific operator to represent it. Instead, concatenation is performed by writing expressions next to one another, with no operator. For example: @example -$ @kbd{awk '@{ print "Field number one: " $1 @}' BBS-list} -@print{} Field number one: aardvark -@print{} Field number one: alpo-net +$ @kbd{awk '@{ print "Field number one: " $1 @}' mail-list} +@print{} Field number one: Amelia +@print{} Field number one: Anthony @dots{} @end example @@ -9817,9 +9947,9 @@ Without the space in the string constant after the @samp{:}, the line runs together. For example: @example -$ @kbd{awk '@{ print "Field number one:" $1 @}' BBS-list} -@print{} Field number one:aardvark -@print{} Field number one:alpo-net +$ @kbd{awk '@{ print "Field number one:" $1 @}' mail-list} +@print{} Field number one:Amelia +@print{} Field number one:Anthony @dots{} @end example @@ -9836,6 +9966,8 @@ name = "name" print "something meaningful" > file name @end example +@cindex Brian Kernighan's @command{awk} +@cindex @command{mawk} utility @noindent This produces a syntax error with some versions of Unix @command{awk}.@footnote{It happens that Brian Kernighan's @@ -10780,10 +10912,10 @@ The Boolean operators are: @item @var{boolean1} && @var{boolean2} True if both @var{boolean1} and @var{boolean2} are true. For example, the following statement prints the current input record if it contains -both @samp{2400} and @samp{foo}: +both @samp{edu} and @samp{li}: @example -if ($0 ~ /2400/ && $0 ~ /foo/) print +if ($0 ~ /edu/ && $0 ~ /li/) print @end example @cindex side effects, Boolean operators @@ -10796,11 +10928,11 @@ no substring @samp{foo} in the record. @item @var{boolean1} || @var{boolean2} True if at least one of @var{boolean1} or @var{boolean2} is true. For example, the following statement prints all records in the input -that contain @emph{either} @samp{2400} or -@samp{foo} or both: +that contain @emph{either} @samp{edu} or +@samp{li} or both: @example -if ($0 ~ /2400/ || $0 ~ /foo/) print +if ($0 ~ /edu/ || $0 ~ /li/) print @end example The subexpression @var{boolean2} is evaluated only if @var{boolean1} @@ -11395,7 +11527,7 @@ slashes (@code{/@var{regexp}/}), or any expression whose string value is used as a dynamic regular expression (@pxref{Computed Regexps}). The following example prints the second field of each input record -whose first field is precisely @samp{foo}: +whose first field is precisely @samp{li}: @cindex @code{/} (forward slash), patterns and @cindex forward slash (@code{/}), patterns and @@ -11404,68 +11536,65 @@ whose first field is precisely @samp{foo}: @cindex @code{!} (exclamation point), @code{!~} operator @cindex exclamation point (@code{!}), @code{!~} operator @example -$ @kbd{awk '$1 == "foo" @{ print $2 @}' BBS-list} +$ @kbd{awk '$1 == "li" @{ print $2 @}' mail-list} @end example @noindent -(There is no output, because there is no BBS site with the exact name @samp{foo}.) +(There is no output, because there is no person with the exact name @samp{li}.) Contrast this with the following regular expression match, which -accepts any record with a first field that contains @samp{foo}: +accepts any record with a first field that contains @samp{li}: @example -$ @kbd{awk '$1 ~ /foo/ @{ print $2 @}' BBS-list} -@print{} 555-1234 +$ @kbd{awk '$1 ~ /foo/ @{ print $2 @}' mail-list} +@print{} 555-5553 @print{} 555-6699 -@print{} 555-6480 -@print{} 555-2127 @end example @cindex regexp constants, as patterns @cindex patterns, regexp constants as A regexp constant as a pattern is also a special case of an expression -pattern. The expression @code{/foo/} has the value one if @samp{foo} -appears in the current input record. Thus, as a pattern, @code{/foo/} -matches any record containing @samp{foo}. +pattern. The expression @code{/li/} has the value one if @samp{li} +appears in the current input record. Thus, as a pattern, @code{/li/} +matches any record containing @samp{li}. @cindex Boolean expressions, as patterns Boolean expressions are also commonly used as patterns. Whether the pattern matches an input record depends on whether its subexpressions match. For example, the following command prints all the records in -@file{BBS-list} that contain both @samp{2400} and @samp{foo}: +@file{mail-list} that contain both @samp{edu} and @samp{li}: @example -$ @kbd{awk '/2400/ && /foo/' BBS-list} -@print{} fooey 555-1234 2400/1200/300 B +$ @kbd{awk '/edu/ && /li/' mail-list} +@print{} Samuel 555-3430 samuel.lanceolis@@shu.edu A @end example The following command prints all records in -@file{BBS-list} that contain @emph{either} @samp{2400} or @samp{foo} +@file{mail-list} that contain @emph{either} @samp{edu} or @samp{li} (or both, of course): @example -$ @kbd{awk '/2400/ || /foo/' BBS-list} -@print{} alpo-net 555-3412 2400/1200/300 A -@print{} bites 555-1675 2400/1200/300 A -@print{} fooey 555-1234 2400/1200/300 B -@print{} foot 555-6699 1200/300 B -@print{} macfoo 555-6480 1200/300 A -@print{} sdace 555-3430 2400/1200/300 A -@print{} sabafoo 555-2127 1200/300 C +$ @kbd{awk '/edu/ || /li/' mail-list} +@print{} Amelia 555-5553 amelia.zodiacusque@@gmail.com F +@print{} Broderick 555-0542 broderick.aliquotiens@@yahoo.com R +@print{} Fabius 555-1234 fabius.undevicesimus@@ucb.edu F +@print{} Julie 555-6699 julie.perscrutabor@@skeeve.com F +@print{} Samuel 555-3430 samuel.lanceolis@@shu.edu A +@print{} Jean-Paul 555-2127 jeanpaul.campanorum@@nyu.edu R @end example The following command prints all records in -@file{BBS-list} that do @emph{not} contain the string @samp{foo}: +@file{mail-list} that do @emph{not} contain the string @samp{li}: @example -$ @kbd{awk '! /foo/' BBS-list} -@print{} aardvark 555-5553 1200/300 B -@print{} alpo-net 555-3412 2400/1200/300 A -@print{} barfly 555-7685 1200/300 A -@print{} bites 555-1675 2400/1200/300 A -@print{} camelot 555-0542 300 C -@print{} core 555-2912 1200/300 C -@print{} sdace 555-3430 2400/1200/300 A +$ @kbd{awk '! /li/' mail-list} +@print{} Anthony 555-3412 anthony.asserturo@@hotmail.com A +@print{} Becky 555-7685 becky.algebrarum@@gmail.com A +@print{} Bill 555-1675 bill.drowning@@hotmail.com A +@print{} Camilla 555-2912 camilla.infusarum@@skynet.be R +@print{} Fabius 555-1234 fabius.undevicesimus@@ucb.edu F +@print{} Martin 555-6480 martin.codicibus@@hotmail.com A +@print{} Jean-Paul 555-2127 jeanpaul.campanorum@@nyu.edu R @end example @cindex @code{BEGIN} pattern, Boolean patterns and @@ -11569,6 +11698,11 @@ $ @kbd{echo Yes | gawk '(/1/,/2/) || /Yes/'} @error{} gawk: cmd. line:1: ^ syntax error @end example +@cindex range patterns, line continuation and +As a minor point of interest, although it is poor style, +POSIX allows you to put a newline after the comma in +a range pattern. @value{DARKCORNER} + @node BEGIN/END @subsection The @code{BEGIN} and @code{END} Special Patterns @@ -11593,28 +11727,30 @@ programmers. @node Using BEGIN/END @subsubsection Startup and Cleanup Actions +@cindex @code{BEGIN} pattern +@cindex @code{END} pattern A @code{BEGIN} rule is executed once only, before the first input record is read. Likewise, an @code{END} rule is executed once only, after all the input is read. For example: @example $ @kbd{awk '} -> @kbd{BEGIN @{ print "Analysis of \"foo\"" @}} -> @kbd{/foo/ @{ ++n @}} -> @kbd{END @{ print "\"foo\" appears", n, "times." @}' BBS-list} -@print{} Analysis of "foo" -@print{} "foo" appears 4 times. +> @kbd{BEGIN @{ print "Analysis of \"li\"" @}} +> @kbd{/li/ @{ ++n @}} +> @kbd{END @{ print "\"li\" appears in", n, "records." @}' mail-list} +@print{} Analysis of "li" +@print{} "li" appears in 4 records. @end example @cindex @code{BEGIN} pattern, operators and @cindex @code{END} pattern, operators and -This program finds the number of records in the input file @file{BBS-list} -that contain the string @samp{foo}. The @code{BEGIN} rule prints a title +This program finds the number of records in the input file @file{mail-list} +that contain the string @samp{li}. The @code{BEGIN} rule prints a title for the report. There is no need to use the @code{BEGIN} rule to initialize the counter @code{n} to zero, since @command{awk} does this automatically (@pxref{Variables}). The second rule increments the variable @code{n} every time a -record containing the pattern @samp{foo} is read. The @code{END} rule +record containing the pattern @samp{li} is read. The @code{END} rule prints the value of @code{n} at the end of the run. The special patterns @code{BEGIN} and @code{END} cannot be used in ranges @@ -11667,6 +11803,7 @@ to give @code{$0} a real value is to execute a @code{getline} command without a variable (@pxref{Getline}). Another way is simply to assign a value to @code{$0}. +@cindex Brian Kernighan's @command{awk} @cindex differences in @command{awk} and @command{gawk}, @code{BEGIN}/@code{END} patterns @cindex POSIX @command{awk}, @code{BEGIN}/@code{END} patterns @cindex @code{print} statement, @code{BEGIN}/@code{END} patterns and @@ -11735,7 +11872,7 @@ you can bypass the fatal error and move on to the next file on the command line. @cindex @command{gawk}, @code{ERRNO} variable in -@cindex @code{ERRNO} variable +@cindex @code{ERRNO} variable, with @code{BEGINFILE} pattern @cindex @code{nextfile} statement, @code{BEGINFILE}/@code{ENDFILE} patterns and You do this by checking if the @code{ERRNO} variable is not the empty string; if so, then @command{gawk} was not able to open the file. In @@ -11777,7 +11914,7 @@ both @code{BEGINFILE} and @code{ENDFILE}. Only the @samp{getline In most other @command{awk} implementations, or if @command{gawk} is in compatibility mode (@pxref{Options}), they are not special. -@c FIXME: For 4.1 maybe deal with this? +@c FIXME: For 4.2 maybe deal with this? @ignore Date: Tue, 17 May 2011 02:06:10 PDT From: rankin@pactechdata.com (Pat Rankin) @@ -11808,7 +11945,7 @@ An empty (i.e., nonexistent) pattern is considered to match @emph{every} input record. For example, the program: @example -awk '@{ print $1 @}' BBS-list +awk '@{ print $1 @}' mail-list @end example @noindent @@ -12061,6 +12198,7 @@ the first thing on its line. @subsection The @code{while} Statement @cindex @code{while} statement @cindex loops +@cindex loops, @code{while} @cindex loops, See Also @code{while} statement In programming, a @dfn{loop} is a part of a program that can @@ -12121,6 +12259,7 @@ program is harder to read without it. @node Do Statement @subsection The @code{do}-@code{while} Statement @cindex @code{do}-@code{while} statement +@cindex loops, @code{do}-@code{while} The @code{do} loop is a variation of the @code{while} looping statement. The @code{do} loop executes the @var{body} once and then repeats the @@ -12166,6 +12305,7 @@ occasionally is there a real use for a @code{do} statement. @node For Statement @subsection The @code{for} Statement @cindex @code{for} statement +@cindex loops, @code{for}, iterative The @code{for} statement makes it more convenient to count iterations of a loop. The general form of the @code{for} statement looks like this: @@ -12272,6 +12412,8 @@ for more information on this version of the @code{for} loop. @cindex @code{case} keyword @cindex @code{default} keyword +This @value{SECTION} describes a @command{gawk}-specific feature. + The @code{switch} statement allows the evaluation of an expression and the execution of statements based on a @code{case} match. Case statements are checked for a match in the order they are defined. If no suitable @@ -12336,6 +12478,7 @@ it is not available. @subsection The @code{break} Statement @cindex @code{break} statement @cindex loops, exiting +@cindex loops, @code{break} statement and The @code{break} statement jumps out of the innermost @code{for}, @code{while}, or @code{do} loop that encloses it. The following example @@ -12395,6 +12538,7 @@ This is discussed in @ref{Switch Statement}. @cindex POSIX @command{awk}, @code{break} statement and @cindex dark corner, @code{break} statement @cindex @command{gawk}, @code{break} statement in +@cindex Brian Kernighan's @command{awk} The @code{break} statement has no meaning when used outside the body of a loop or @code{switch}. However, although it was never documented, @@ -12459,6 +12603,7 @@ This program loops forever once @code{x} reaches 5. @cindex POSIX @command{awk}, @code{continue} statement and @cindex dark corner, @code{continue} statement @cindex @command{gawk}, @code{continue} statement in +@cindex Brian Kernighan's @command{awk} The @code{continue} statement has no special meaning with respect to the @code{switch} statement, nor does it have any meaning when used outside the body of a loop. Historical versions of @command{awk} treated a @code{continue} @@ -12596,8 +12741,10 @@ See @uref{http://austingroupbugs.net/view.php?id=607, the Austin Group website}. @cindex functions, user-defined, @code{next}/@code{nextfile} statements and @cindex @code{nextfile} statement, user-defined functions and -The current version of the Brian Kernighan's @command{awk} (@pxref{Other -Versions}) also supports @code{nextfile}. However, it doesn't allow the +@cindex Brian Kernighan's @command{awk} +@cindex @command{mawk} utility +The current version of the Brian Kernighan's @command{awk}, and @command{mawk} (@pxref{Other +Versions}) also support @code{nextfile}. However, they don't allow the @code{nextfile} statement inside function bodies (@pxref{User-defined}). @command{gawk} does; a @code{nextfile} inside a function body reads the next record and starts processing it with the first rule in the program, @@ -12834,8 +12981,8 @@ is to simply say @samp{FS = FS}, perhaps with an explanatory comment. @cindex @command{gawk}, @code{IGNORECASE} variable in @cindex @code{IGNORECASE} variable @cindex differences in @command{awk} and @command{gawk}, @code{IGNORECASE} variable -@cindex case sensitivity, string comparisons and -@cindex case sensitivity, regexps and +@cindex case sensitivity, and string comparisons +@cindex case sensitivity, and regexps @cindex regular expressions, case sensitivity @item IGNORECASE # If @code{IGNORECASE} is nonzero or non-null, then all string comparisons @@ -13000,16 +13147,16 @@ In the following example: $ @kbd{awk 'BEGIN @{} > @kbd{for (i = 0; i < ARGC; i++)} > @kbd{print ARGV[i]} -> @kbd{@}' inventory-shipped BBS-list} +> @kbd{@}' inventory-shipped mail-list} @print{} awk @print{} inventory-shipped -@print{} BBS-list +@print{} mail-list @end example @noindent @code{ARGV[0]} contains @samp{awk}, @code{ARGV[1]} contains @samp{inventory-shipped}, and @code{ARGV[2]} contains -@samp{BBS-list}. The value of @code{ARGC} is three, one more than the +@samp{mail-list}. The value of @code{ARGC} is three, one more than the index of the last element in @code{ARGV}, because the elements are numbered from zero. @@ -13052,7 +13199,7 @@ or if @command{gawk} is in compatibility mode it is not special. @cindex @code{ENVIRON} array -@cindex environment variables +@cindex environment variables, in @code{ENVIRON} array @item ENVIRON An associative array containing the values of the environment. The array indices are the environment variable names; the elements are the values of @@ -13175,10 +13322,12 @@ The following elements (listed alphabetically) are guaranteed to be available: @table @code +@cindex effective group ID of @command{gawk} user @item PROCINFO["egid"] The value of the @code{getegid()} system call. @item PROCINFO["euid"] +@cindex effective user ID of @command{gawk} user The value of the @code{geteuid()} system call. @item PROCINFO["FS"] @@ -13188,6 +13337,7 @@ This is or @code{"FPAT"} if field matching with @code{FPAT} is in effect. @item PROCINFO["identifiers"] +@cindex program identifiers A subarray, indexed by the names of all identifiers used in the text of the AWK program. For each identifier, the value of the element is one of the following: @@ -13216,15 +13366,19 @@ after it has finished parsing the program; they are @emph{not} updated while the program runs. @item PROCINFO["gid"] +@cindex group ID of @command{gawk} user The value of the @code{getgid()} system call. @item PROCINFO["pgrpid"] +@cindex process group idIDof @command{gawk} process The process group ID of the current process. @item PROCINFO["pid"] +@cindex process ID of @command{gawk} process The process ID of the current process. @item PROCINFO["ppid"] +@cindex parent process ID of @command{gawk} process The parent process ID of the current process. @item PROCINFO["sorted_in"] @@ -13244,25 +13398,31 @@ Assigning a new value to this element changes the default. The value of the @code{getuid()} system call. @item PROCINFO["version"] +@cindex version of @command{gawk} +@cindex @command{gawk} version The version of @command{gawk}. @end table The following additional elements in the array are available to provide information about the MPFR and GMP libraries if your version of @command{gawk} supports arbitrary precision numbers -(@pxref{Arbitrary Precision Arithmetic}): +(@pxref{Gawk and MPFR}): @table @code +@cindex version of GNU MPFR library @item PROCINFO["mpfr_version"] The version of the GNU MPFR library. @item PROCINFO["gmp_version"] +@cindex version of GNU MP library The version of the GNU MP library. @item PROCINFO["prec_max"] +@cindex maximum precision supported by MPFR library The maximum precision supported by MPFR. @item PROCINFO["prec_min"] +@cindex minimum precision supported by MPFR library The minimum precision required by MPFR. @end table @@ -13273,12 +13433,15 @@ of @command{gawk} supports dynamic loading of extension functions @table @code @item PROCINFO["api_major"] +@cindex version of @command{gawk} extension API +@cindex extension API, version number The major version of the extension API. @item PROCINFO["api_minor"] The minor version of the extension API. @end table +@cindex supplementary groups of @command{gawk} process On some systems, there may be elements in the array, @code{"group1"} through @code{"group@var{N}"} for some @var{N}. @var{N} is the number of supplementary groups that the process has. Use the @code{in} operator @@ -13286,7 +13449,7 @@ to test for these elements (@pxref{Reference to Elements}). @cindex @command{gawk}, @code{PROCINFO} array in -@cindex @code{PROCINFO} array +@cindex @code{PROCINFO} array, uses The @code{PROCINFO} array has the following additional uses: @itemize @bullet @@ -13358,7 +13521,7 @@ if an element in @code{SYMTAB} is an array. Also, you may not use the @code{delete} statement with the @code{SYMTAB} array. -You may use an index for @code{SYMTAB} that is not a predefined identifer: +You may use an index for @code{SYMTAB} that is not a predefined identifier: @example SYMTAB["xxx"] = 5 @@ -13426,7 +13589,7 @@ changed. @node ARGC and ARGV @subsection Using @code{ARGC} and @code{ARGV} -@cindex @code{ARGC}/@code{ARGV} variables +@cindex @code{ARGC}/@code{ARGV} variables, how to use @cindex arguments, command-line @cindex command line, arguments @@ -13438,16 +13601,16 @@ and @code{ARGV}: $ @kbd{awk 'BEGIN @{} > @kbd{for (i = 0; i < ARGC; i++)} > @kbd{print ARGV[i]} -> @kbd{@}' inventory-shipped BBS-list} +> @kbd{@}' inventory-shipped mail-list} @print{} awk @print{} inventory-shipped -@print{} BBS-list +@print{} mail-list @end example @noindent In this example, @code{ARGV[0]} contains @samp{awk}, @code{ARGV[1]} contains @samp{inventory-shipped}, and @code{ARGV[2]} contains -@samp{BBS-list}. +@samp{mail-list}. Notice that the @command{awk} program is not entered in @code{ARGV}. The other command-line options, with their arguments, are also not entered. This includes variable assignments done with the @option{-v} @@ -13571,7 +13734,7 @@ ability to support true multidimensional arrays. @cindex variables, names of @cindex functions, names of -@cindex arrays, names of +@cindex arrays, names of, and names of functions/variables @cindex names, arrays/variables @cindex namespace issues @command{awk} maintains a single set @@ -13747,10 +13910,9 @@ Here, the number @code{1} isn't double-quoted, since @command{awk} automatically converts it to a string. @cindex @command{gawk}, @code{IGNORECASE} variable in -@cindex @code{IGNORECASE} variable @cindex case sensitivity, array indices and -@cindex arrays, @code{IGNORECASE} variable and -@cindex @code{IGNORECASE} variable, array subscripts and +@cindex arrays, and @code{IGNORECASE} variable +@cindex @code{IGNORECASE} variable, and array indices The value of @code{IGNORECASE} has no effect upon array subscripting. The identical string value used to store an array element must be used to retrieve it. @@ -13766,8 +13928,9 @@ is independent of the number of elements in the array. @node Reference to Elements @subsection Referring to an Array Element -@cindex arrays, elements, referencing -@cindex elements in arrays +@cindex arrays, referencing elements +@cindex array members +@cindex elements of arrays The principal way to use an array is to refer to one of its elements. An array reference is an expression as follows: @@ -13784,11 +13947,16 @@ The value of the array reference is the current value of that array element. For example, @code{foo[4.3]} is an expression for the element of array @code{foo} at index @samp{4.3}. +@cindex arrays, unassigned elements +@cindex unassigned array elements +@cindex empty array elements A reference to an array element that has no recorded value yields a value of @code{""}, the null string. This includes elements that have not been assigned any value as well as elements that have been deleted (@pxref{Delete}). +@cindex non-existent array elements +@cindex arrays, elements that don't exist @quotation NOTE A reference to an element that does not exist @emph{automatically} creates that array element, with the null string as its value. (In some cases, @@ -13808,7 +13976,7 @@ if it didn't exist before! @end quotation @c @cindex arrays, @code{in} operator and -@cindex @code{in} operator +@cindex @code{in} operator, testing if array element exists To determine whether an element exists in an array at a certain index, use the following expression: @@ -13843,8 +14011,8 @@ if (frequencies[2] != "") @node Assigning Elements @subsection Assigning Array Elements -@cindex arrays, elements, assigning -@cindex elements in arrays, assigning +@cindex arrays, elements, assigning values +@cindex elements in arrays, assigning values Array elements can be assigned values just like @command{awk} variables: @@ -13861,6 +14029,7 @@ assign to that element of the array. @node Array Example @subsection Basic Array Example +@cindex arrays, an example of using The following program takes a list of lines, each beginning with a line number, and prints them out in order of line number. The line numbers @@ -13930,7 +14099,9 @@ END @{ @node Scanning an Array @subsection Scanning All Elements of an Array @cindex elements in arrays, scanning +@cindex scanning arrays @cindex arrays, scanning +@cindex loops, @code{for}, array scanning In programs that use arrays, it is often necessary to use a loop that executes once for each element of an array. In other languages, where @@ -13947,7 +14118,7 @@ for (@var{var} in @var{array}) @end example @noindent -@cindex @code{in} operator +@cindex @code{in} operator, use in loops This loop executes @var{body} once for each index in @var{array} that the program has previously used, with the variable @var{var} set to that index. @@ -13986,8 +14157,9 @@ END @{ @xref{Word Sorting}, for a more detailed example of this type. -@cindex arrays, elements, order of -@cindex elements in arrays, order of +@cindex arrays, elements, order of access by @code{in} operator +@cindex elements in arrays, order of access by @code{in} operator +@cindex @code{in} operator, order of array access The order in which elements of the array are accessed by this statement is determined by the internal arrangement of the array elements within @command{awk} and normally cannot be controlled or changed. This can lead to @@ -14005,6 +14177,8 @@ determines the order in which the array is traversed. This order is usually based on the internal implementation of arrays and will vary from one version of @command{awk} to the next. +@cindex array scanning order, controlling +@cindex controlling array scanning order Often, though, you may wish to do something simple, such as ``traverse the array by comparing the indices in ascending order,'' or ``traverse the array by comparing the values in descending order.'' @@ -14021,6 +14195,7 @@ to use for comparison of array elements. This advanced feature is described later, in @ref{Array Sorting}. @end itemize +@cindex @code{PROCINFO}, values of @code{sorted_in} The following special values for @code{PROCINFO["sorted_in"]} are available: @table @code @@ -14181,7 +14356,7 @@ if (4 in foo) print "This will never be printed" @end example -@cindex null strings, array elements and +@cindex null strings, and deleting array elements It is important to note that deleting an element is @emph{not} the same as assigning it a null value (the empty string, @code{""}). For example: @@ -14203,6 +14378,7 @@ is not in the array is deleted. @cindex extensions, common@comma{} @code{delete} to delete entire arrays @cindex arrays, deleting entire contents @cindex deleting entire arrays +@cindex @code{delete} @var{array} @cindex differences in @command{awk} and @command{gawk}, array elements, deleting All the elements of an array may be deleted with a single statement by leaving off the subscript in the @code{delete} statement, @@ -14217,6 +14393,7 @@ Using this version of the @code{delete} statement is about three times more efficient than the equivalent loop that deletes each element one at a time. +@cindex Brian Kernighan's @command{awk} @quotation NOTE For many years, using @code{delete} without a subscript was a @command{gawk} extension. @@ -14259,9 +14436,9 @@ a = 3 @section Using Numbers to Subscript Arrays @cindex numbers, as array subscripts -@cindex arrays, subscripts +@cindex arrays, numeric subscripts @cindex subscripts in arrays, numbers as -@cindex @code{CONVFMT} variable, array subscripts and +@cindex @code{CONVFMT} variable, and array subscripts An important aspect to remember about arrays is that @emph{array subscripts are always strings}. When a numeric value is used as a subscript, it is converted to a string value before being used for subscripting @@ -14291,7 +14468,8 @@ string value from @code{xyz}---this time @code{"12.15"}---because the value of @code{CONVFMT} only allows two significant digits. This test fails, since @code{"12.15"} is different from @code{"12.153"}. -@cindex converting, during subscripting +@cindex converting integer array subscripts +@cindex integer array indices According to the rules for conversions (@pxref{Conversion}), integer values are always converted to strings as integers, no matter what the @@ -14397,7 +14575,7 @@ languages, including @command{awk}) to refer to an element of a two-dimensional array named @code{grid} is with @code{grid[@var{x},@var{y}]}. -@cindex @code{SUBSEP} variable, multidimensional arrays +@cindex @code{SUBSEP} variable, and multidimensional arrays Multidimensional arrays are supported in @command{awk} through concatenation of indices into one string. @command{awk} converts the indices into strings @@ -14429,6 +14607,7 @@ combined strings that are ambiguous. Suppose that @code{SUBSEP} is "b@@c"]}} are indistinguishable because both are actually stored as @samp{foo["a@@b@@c"]}. +@cindex @code{in} operator, index existence in multidimensional arrays To test whether a particular index sequence exists in a multidimensional array, use the same operator (@code{in}) that is used for single dimensional arrays. Write the whole sequence of indices @@ -14494,6 +14673,7 @@ multidimensional @emph{way of accessing} an array. @cindex subscripts in arrays, multidimensional, scanning @cindex arrays, multidimensional, scanning +@cindex scanning multidimensional arrays However, if your program has an array that is always accessed as multidimensional, you can get the effect of scanning it by combining the scanning @code{for} statement @@ -14535,6 +14715,7 @@ separate indices is recovered. @node Arrays of Arrays @section Arrays of Arrays +@cindex arrays of arrays @command{gawk} goes beyond standard @command{awk}'s multidimensional array access and provides true arrays of @@ -14794,6 +14975,7 @@ two arguments 11 and 10. @node Numeric Functions @subsection Numeric Functions +@cindex numeric functions The following list describes all of the built-in functions that work with numbers. @@ -14801,22 +14983,26 @@ Optional parameters are enclosed in square brackets@w{ ([ ]):} @table @code @item atan2(@var{y}, @var{x}) -@cindex @code{atan2()} function +@cindexawkfunc{atan2} +@cindex arctangent Return the arctangent of @code{@var{y} / @var{x}} in radians. You can use @samp{pi = atan2(0, -1)} to retrieve the value of @value{PI}. @item cos(@var{x}) -@cindex @code{cos()} function +@cindexawkfunc{cos} +@cindex cosine Return the cosine of @var{x}, with @var{x} in radians. @item exp(@var{x}) -@cindex @code{exp()} function +@cindexawkfunc{exp} +@cindex exponent Return the exponential of @var{x} (@code{e ^ @var{x}}) or report an error if @var{x} is out of range. The range of values @var{x} can have depends on your machine's floating-point representation. @item int(@var{x}) -@cindex @code{int()} function +@cindexawkfunc{int} +@cindex round to nearest integer Return the nearest integer to @var{x}, located between @var{x} and zero and truncated toward zero. @@ -14824,12 +15010,13 @@ For example, @code{int(3)} is 3, @code{int(3.9)} is 3, @code{int(-3.9)} is @minus{}3, and @code{int(-3)} is @minus{}3 as well. @item log(@var{x}) -@cindex @code{log()} function +@cindexawkfunc{log} +@cindex logarithm Return the natural logarithm of @var{x}, if @var{x} is positive; otherwise, report an error. @item rand() -@cindex @code{rand()} function +@cindexawkfunc{rand} @cindex random numbers, @code{rand()}/@code{srand()} functions Return a random number. The values of @code{rand()} are uniformly distributed between zero and one. @@ -14871,7 +15058,7 @@ function roll(n) @{ return 1 + int(rand() * n) @} @} @end example -@cindex numbers, random +@cindex seeding random number generator @cindex random numbers, seed of @quotation CAUTION In most @command{awk} implementations, including @command{gawk}, @@ -14887,17 +15074,19 @@ use @code{srand()}. @end quotation @item sin(@var{x}) -@cindex @code{sin()} function +@cindexawkfunc{sin} +@cindex sine Return the sine of @var{x}, with @var{x} in radians. @item sqrt(@var{x}) -@cindex @code{sqrt()} function +@cindexawkfunc{sqrt} +@cindex square root Return the positive square root of @var{x}. @command{gawk} prints a warning message if @var{x} is negative. Thus, @code{sqrt(4)} is 2. @item srand(@r{[}@var{x}@r{]}) -@cindex @code{srand()} function +@cindexawkfunc{srand} Set the starting point, or seed, for generating random numbers to the value @var{x}. @@ -14927,6 +15116,7 @@ sequences of random numbers. @node String Functions @subsection String-Manipulation Functions +@cindex string-manipulation functions The functions in this @value{SECTION} look at or change the text of one or more strings. @@ -14955,11 +15145,11 @@ pound sign@w{ (@samp{#}):} @table @code @item asort(@var{source} @r{[}, @var{dest} @r{[}, @var{how} @r{]} @r{]}) # @itemx asorti(@var{source} @r{[}, @var{dest} @r{[}, @var{how} @r{]} @r{]}) # -@cindex @code{asorti()} function (@command{gawk}) +@cindexgawkfunc{asorti} +@cindex sort array @cindex arrays, elements, retrieving number of -@cindex @code{asort()} function (@command{gawk}) -@cindex @command{gawk}, @code{IGNORECASE} variable in -@cindex @code{IGNORECASE} variable +@cindexgawkfunc{asort} +@cindex sort array indices These two functions are similar in behavior, so they are described together. @@ -14977,7 +15167,9 @@ sequential integers starting with one. If the optional array @var{dest} is specified, then @var{source} is duplicated into @var{dest}. @var{dest} is then sorted, leaving the indices of @var{source} unchanged. -When comparing strings, @code{IGNORECASE} affects the sorting. If the +@cindex @command{gawk}, @code{IGNORECASE} variable in +When comparing strings, @code{IGNORECASE} affects the sorting +(@pxref{Array Sorting Functions}). If the @var{source} array contains subarrays as values (@pxref{Arrays of Arrays}), they will come last, after all scalar values. @@ -15020,7 +15212,9 @@ a[3] = "middle" are not available in compatibility mode (@pxref{Options}). @item gensub(@var{regexp}, @var{replacement}, @var{how} @r{[}, @var{target}@r{]}) # -@cindex @code{gensub()} function (@command{gawk}) +@cindexgawkfunc{gensub} +@cindex search and replace in strings +@cindex substitute in string Search the target string @var{target} for matches of the regular expression @var{regexp}. If @var{how} is a string beginning with @samp{g} or @samp{G} (short for ``global''), then replace all matches of @var{regexp} with @@ -15029,7 +15223,7 @@ which match of @var{regexp} to replace. If no @var{target} is supplied, use @code{$0}. It returns the modified string as the result of the function and the original target string is @emph{not} changed. -@code{gensub()} is a general substitution function. It's purpose is +@code{gensub()} is a general substitution function. Its purpose is to provide more features than the standard @code{sub()} and @code{gsub()} functions. @@ -15083,7 +15277,7 @@ is the original unchanged value of @var{target}. in compatibility mode (@pxref{Options}). @item gsub(@var{regexp}, @var{replacement} @r{[}, @var{target}@r{]}) -@cindex @code{gsub()} function +@cindexawkfunc{gsub} Search @var{target} for @emph{all} of the longest, leftmost, @emph{nonoverlapping} matching substrings it can find and replace them with @var{replacement}. @@ -15105,8 +15299,9 @@ As in @code{sub()}, the characters @samp{&} and @samp{\} are special, and the third argument must be assignable. @item index(@var{in}, @var{find}) -@cindex @code{index()} function -@cindex searching +@cindexawkfunc{index} +@cindex search in string +@cindex find substring in string Search the string @var{in} for the first occurrence of the string @var{find}, and return the position in characters where that occurrence begins in the string @var{in}. Consider the following example: @@ -15123,7 +15318,9 @@ If @var{find} is not found, @code{index()} returns zero. It is a fatal error to use a regexp constant for @var{find}. @item length(@r{[}@var{string}@r{]}) -@cindex @code{length()} function +@cindexawkfunc{length} +@cindex string length +@cindex length of string Return the number of characters in @var{string}. If @var{string} is a number, the length of the digit string representing that number is returned. For example, @code{length("abcde")} is five. By @@ -15131,6 +15328,8 @@ contrast, @code{length(15 * 35)} works out to three. In this example, 15 * 35 = 525, and 525 is then converted to the string @code{"525"}, which has three characters. +@cindex length of input record +@cindex input record, length of If no argument is supplied, @code{length()} returns the length of @code{$0}. @c @cindex historical features @@ -15169,6 +15368,8 @@ warning about this. @cindex common extensions, @code{length()} applied to an array @cindex extensions, common@comma{} @code{length()} applied to an array @cindex differences between @command{gawk} and @command{awk} +@cindex number of array elements +@cindex array, number of elements With @command{gawk} and several other @command{awk} implementations, when given an array argument, the @code{length()} function returns the number of elements in the array. @value{COMMONEXT} @@ -15182,7 +15383,9 @@ If @option{--posix} is supplied, using an array argument is a fatal error (@pxref{Arrays}). @item match(@var{string}, @var{regexp} @r{[}, @var{array}@r{]}) -@cindex @code{match()} function +@cindexawkfunc{match} +@cindex string, regular expression match +@cindex match regexp in string Search @var{string} for the longest, leftmost substring matched by the regular expression, @var{regexp} and return the character position, or @dfn{index}, @@ -15297,7 +15500,8 @@ The @var{array} argument to @code{match()} is a using a third argument is a fatal error. @item patsplit(@var{string}, @var{array} @r{[}, @var{fieldpat} @r{[}, @var{seps} @r{]} @r{]}) # -@cindex @code{patsplit()} function (@command{gawk}) +@cindexgawkfunc{patsplit} +@cindex split string into array Divide @var{string} into pieces defined by @var{fieldpat} and store the pieces in @var{array} and the separator strings in the @@ -15328,7 +15532,7 @@ The @code{patsplit()} function is a it is not available. @item split(@var{string}, @var{array} @r{[}, @var{fieldsep} @r{[}, @var{seps} @r{]} @r{]}) -@cindex @code{split()} function +@cindexawkfunc{split} Divide @var{string} into pieces separated by @var{fieldsep} and store the pieces in @var{array} and the separator strings in the @var{seps} array. The first piece is stored in @@ -15357,7 +15561,7 @@ split("cul-de-sac", a, "-", seps) @end example @noindent -@cindex strings, splitting +@cindex strings splitting, example splits the string @samp{cul-de-sac} into three fields using @samp{-} as the separator. It sets the contents of the array @code{a} as follows: @@ -15413,7 +15617,8 @@ If @var{string} does not match @var{fieldsep} at all (but is not null), @var{string}. @item sprintf(@var{format}, @var{expression1}, @dots{}) -@cindex @code{sprintf()} function +@cindexawkfunc{sprintf} +@cindex formatting strings Return (without printing) the string that @code{printf} would have printed out with the same arguments (@pxref{Printf}). @@ -15426,7 +15631,8 @@ pival = sprintf("pi = %.2f (approx.)", 22/7) @noindent assigns the string @w{@samp{pi = 3.14 (approx.)}} to the variable @code{pival}. -@cindex @code{strtonum()} function (@command{gawk}) +@cindexgawkfunc{strtonum} +@cindex convert string to number @item strtonum(@var{str}) # Examine @var{str} and return its numeric value. If @var{str} begins with a leading @samp{0}, @code{strtonum()} assumes that @var{str} @@ -15449,12 +15655,12 @@ you use the @option{--non-decimal-data} option, which isn't recommended. Note also that @code{strtonum()} uses the current locale's decimal point for recognizing numbers (@pxref{Locales}). -@cindex differences in @command{awk} and @command{gawk}, @code{strtonum()} function (@command{gawk}) @code{strtonum()} is a @command{gawk} extension; it is not available in compatibility mode (@pxref{Options}). @item sub(@var{regexp}, @var{replacement} @r{[}, @var{target}@r{]}) -@cindex @code{sub()} function +@cindexawkfunc{sub} +@cindex replace in string Search @var{target}, which is treated as a string, for the leftmost, longest substring matched by the regular expression @var{regexp}. Modify the entire string @@ -15554,7 +15760,8 @@ Finally, if the @var{regexp} is not a regexp constant, it is converted into a string, and then the value of that string is treated as the regexp to match. @item substr(@var{string}, @var{start} @r{[}, @var{length}@r{]}) -@cindex @code{substr()} function +@cindexawkfunc{substr} +@cindex substring Return a @var{length}-character-long substring of @var{string}, starting at character number @var{start}. The first character of a string is character number one.@footnote{This is different from @@ -15568,6 +15775,7 @@ suffix is also returned if @var{length} is greater than the number of characters remaining in the string, counting from character @var{start}. +@cindex Brian Kernighan's @command{awk} If @var{start} is less than one, @code{substr()} treats it as if it was one. (POSIX doesn't specify what to do in this case: Brian Kernighan's @command{awk} acts this way, and therefore @command{gawk} @@ -15610,16 +15818,18 @@ string = substr(string, 1, 2) "CDE" substr(string, 6) @end example @cindex case sensitivity, converting case -@cindex converting, case +@cindex strings, converting letter case @item tolower(@var{string}) -@cindex @code{tolower()} function +@cindexawkfunc{tolower} +@cindex convert string to lower case Return a copy of @var{string}, with each uppercase character in the string replaced with its corresponding lowercase character. Nonalphabetic characters are left unchanged. For example, @code{tolower("MiXeD cAsE 123")} returns @code{"mixed case 123"}. @item toupper(@var{string}) -@cindex @code{toupper()} function +@cindexawkfunc{toupper} +@cindex convert string to upper case Return a copy of @var{string}, with each lowercase character in the string replaced with its corresponding uppercase character. Nonalphabetic characters are left unchanged. For example, @@ -15647,6 +15857,7 @@ and builds an internal copy of it that can be executed. Then there is the runtime level, which is when @command{awk} actually scans the replacement string to determine what to generate. +@cindex Brian Kernighan's @command{awk} At both levels, @command{awk} looks for a defined set of characters that can come after a backslash. At the lexical level, it looks for the escape sequences listed in @ref{Escape Sequences}. @@ -16011,14 +16222,16 @@ Although this makes a certain amount of sense, it can be surprising. @node I/O Functions @subsection Input/Output Functions +@cindex input/output functions The following functions relate to input/output (I/O). Optional parameters are enclosed in square brackets ([ ]): @table @code @item close(@var{filename} @r{[}, @var{how}@r{]}) -@cindex @code{close()} function +@cindexawkfunc{close} @cindex files, closing +@cindex close file or coprocess Close the file @var{filename} for input or output. Alternatively, the argument may be a shell command that was used for creating a coprocess, or for redirecting to or from a pipe; then the coprocess or pipe is closed. @@ -16035,7 +16248,8 @@ not matter. which discusses this feature in more detail and gives an example. @item fflush(@r{[}@var{filename}@r{]}) -@cindex @code{fflush()} function +@cindexawkfunc{fflush} +@cindex flush buffered output Flush any buffered output associated with @var{filename}, which is either a file opened for writing or a shell command for redirecting output to a pipe or coprocess. @@ -16053,11 +16267,12 @@ This is the purpose of the @code{fflush()} function---@command{gawk} also buffers its output and the @code{fflush()} function forces @command{gawk} to flush its buffers. -@code{fflush()} was added to Brian Kernighan's -version of @command{awk} in 1994. -For over two decades, it was not part of the POSIX standard. -As of December, 2012, it was accepted for -inclusion into the POSIX standard. +@cindex extensions, common@comma{} @code{fflush()} function +@cindex Brian Kernighan's @command{awk} +@code{fflush()} was added to Brian Kernighan's version of @command{awk} in +April of 1992. For two decades, it was not part of the POSIX standard. +As of December, 2012, it was accepted for inclusion into the POSIX +standard. See @uref{http://austingroupbugs.net/view.php?id=634, the Austin Group website}. POSIX standardizes @code{fflush()} as follows: If there @@ -16093,7 +16308,8 @@ or if @var{filename} is not an open file, pipe, or coprocess. In such a case, @code{fflush()} returns @minus{}1, as well. @item system(@var{command}) -@cindex @code{system()} function +@cindexawkfunc{system} +@cindex invoke shell command @cindex interacting with other programs Execute the operating-system command @var{command} and then return to the @command{awk} program. @@ -16240,6 +16456,7 @@ you would see the latter (undesirable) output. @node Time Functions @subsection Time Functions +@cindex time functions @c STARTOFRANGE tst @cindex timestamps @@ -16259,7 +16476,18 @@ it is the number of seconds since 1970-01-01 00:00:00 UTC, not counting leap seconds.@footnote{@xref{Glossary}, especially the entries ``Epoch'' and ``UTC.''} All known POSIX-compliant systems support timestamps from 0 through -@math{2^{31} - 1}, which is sufficient to represent times through +@iftex +@math{2^{31} - 1}, +@end iftex +@ifnottex +@ifnotdocbook +2^31 - 1, +@end ifnotdocbook +@end ifnottex +@docbook +2<superscript>31</superscript> − 1, @c +@end docbook +which is sufficient to represent times through 2038-01-19 03:14:07 UTC. Many systems support a wider range of timestamps, including negative timestamps that represent times before the epoch. @@ -16278,7 +16506,8 @@ Optional parameters are enclosed in square brackets ([ ]): @table @code @item mktime(@var{datespec}) -@cindex @code{mktime()} function (@command{gawk}) +@cindexgawkfunc{mktime} +@cindex generate time values Turn @var{datespec} into a timestamp in the same form as is returned by @code{systime()}. It is similar to the function of the same name in ISO C. The argument, @var{datespec}, is a string of the form @@ -16308,7 +16537,8 @@ is out of range, @code{mktime()} returns @minus{}1. @cindex @code{PROCINFO} array @item strftime(@r{[}@var{format} @r{[}, @var{timestamp} @r{[}, @var{utc-flag}@r{]]]}) @c STARTOFRANGE strf -@cindex @code{strftime()} function (@command{gawk}) +@cindexgawkfunc{strftime} +@cindex format time string Format the time specified by @var{timestamp} based on the contents of the @var{format} string and return the result. It is similar to the function of the same name in ISO C. @@ -16325,11 +16555,12 @@ The default string value is @code{@w{"%a %b %e %H:%M:%S %Z %Y"}}. This format string produces output that is equivalent to that of the @command{date} utility. You can assign a new value to @code{PROCINFO["strftime"]} to -change the default format. +change the default format; see below for the various format directives. @item systime() -@cindex @code{systime()} function (@command{gawk}) +@cindexgawkfunc{systime} @cindex timestamps +@cindex current system time Return the current time as the number of seconds since the system epoch. On POSIX systems, this is the number of seconds since 1970-01-01 00:00:00 UTC, not counting leap seconds. @@ -16623,6 +16854,7 @@ gawk 'BEGIN @{ @node Bitwise Functions @subsection Bit-Manipulation Functions +@cindex bit-manipulation functions @c STARTOFRANGE bit @cindex bitwise, operations @c STARTOFRANGE and @@ -16785,27 +17017,33 @@ bitwise operations just described. They are: @cindex @command{gawk}, bitwise operations in @table @code -@cindex @code{and()} function (@command{gawk}) +@cindexgawkfunc{and} +@cindex bitwise AND @item and(@var{v1}, @var{v2} @r{[}, @r{@dots{}]}) Return the bitwise AND of the arguments. There must be at least two. -@cindex @code{compl()} function (@command{gawk}) +@cindexgawkfunc{compl} +@cindex bitwise complement @item compl(@var{val}) Return the bitwise complement of @var{val}. -@cindex @code{lshift()} function (@command{gawk}) +@cindexgawkfunc{lshift} +@cindex left shift @item lshift(@var{val}, @var{count}) Return the value of @var{val}, shifted left by @var{count} bits. -@cindex @code{or()} function (@command{gawk}) +@cindexgawkfunc{or} +@cindex bitwise OR @item or(@var{v1}, @var{v2} @r{[}, @r{@dots{}]}) Return the bitwise OR of the arguments. There must be at least two. -@cindex @code{rshift()} function (@command{gawk}) +@cindexgawkfunc{rshift} +@cindex right shift @item rshift(@var{val}, @var{count}) Return the value of @var{val}, shifted right by @var{count} bits. -@cindex @code{xor()} function (@command{gawk}) +@cindexgawkfunc{xor} +@cindex bitwise XOR @item xor(@var{v1}, @var{v2} @r{[}, @r{@dots{}]}) Return the bitwise XOR of the arguments. There must be at least two. @end table @@ -16897,6 +17135,7 @@ $ @kbd{gawk -f testbits.awk} @cindex strings, converting @cindex numbers, converting @cindex converting, numbers to strings +@cindex number as string of bits The @code{bits2str()} function turns a binary number into a string. The number @code{1} represents a binary value where the rightmost bit is set to 1. Using this mask, @@ -16932,7 +17171,8 @@ that traverses every element of a true multidimensional array (@pxref{Arrays of Arrays}). @table @code -@cindex @code{isarray()} function (@command{gawk}) +@cindexgawkfunc{isarray} +@cindex scalar or array @item isarray(@var{x}) Return a true value if @var{x} is an array. Otherwise return false. @end table @@ -16940,7 +17180,7 @@ Return a true value if @var{x} is an array. Otherwise return false. @code{isarray()} is meant for use in two circumstances. The first is when traversing a multidimensional array: you can test if an element is itself an array or not. The second is inside the body of a user-defined function -(not discussed yet; @pxref{User-defined}), to test if a paramater is an +(not discussed yet; @pxref{User-defined}), to test if a parameter is an array or not. Note, however, that using @code{isarray()} at the global level to test @@ -16954,6 +17194,7 @@ will end up turning it into a scalar. @subsection String-Translation Functions @cindex @command{gawk}, string-translation functions @cindex functions, string-translation +@cindex string-translation functions @cindex internationalization @cindex @command{awk} programs, internationalizing @@ -16965,7 +17206,8 @@ for the full story. Optional parameters are enclosed in square brackets ([ ]): @table @code -@cindex @code{bindtextdomain()} function (@command{gawk}) +@cindexgawkfunc{bindtextdomain} +@cindex set directory of message catalogs @item bindtextdomain(@var{directory} @r{[}, @var{domain}@r{]}) Set the directory in which @command{gawk} will look for message translation files, in case they @@ -16978,14 +17220,15 @@ If @var{directory} is the null string (@code{""}), then @code{bindtextdomain()} returns the current binding for the given @var{domain}. -@cindex @code{dcgettext()} function (@command{gawk}) +@cindexgawkfunc{dcgettext} +@cindex translate string @item dcgettext(@var{string} @r{[}, @var{domain} @r{[}, @var{category}@r{]]}) Return the translation of @var{string} in text domain @var{domain} for locale category @var{category}. The default value for @var{domain} is the current value of @code{TEXTDOMAIN}. The default value for @var{category} is @code{"LC_MESSAGES"}. -@cindex @code{dcngettext()} function (@command{gawk}) +@cindexgawkfunc{dcngettext} @item dcngettext(@var{string1}, @var{string2}, @var{number} @r{[}, @var{domain} @r{[}, @var{category}@r{]]}) Return the plural form used for @var{number} of the translation of @var{string1} and @var{string2} in text domain @@ -17002,7 +17245,7 @@ The default value for @var{category} is @code{"LC_MESSAGES"}. @section User-Defined Functions @c STARTOFRANGE udfunc -@cindex user-defined, functions +@cindex user-defined functions @c STARTOFRANGE funcud @cindex functions, user-defined Complicated @command{awk} programs can often be simplified by defining @@ -17061,7 +17304,7 @@ have a parameter with the same name as the function itself. In addition, according to the POSIX standard, function parameters cannot have the same name as one of the special built-in variables (@pxref{Built-in Variables}. Not all versions of @command{awk} -enforce this restriction. +enforce this restriction.) The @var{body-of-function} consists of @command{awk} statements. It is the most important part of the definition, because it says what the function @@ -17088,6 +17331,7 @@ conventional to place some extra space between the arguments and the local variables, in order to document how your function is supposed to be used. @cindex variables, shadowing +@cindex shadowing of variable values During execution of the function body, the arguments and local variable values hide, or @dfn{shadow}, any variables of the same names used in the rest of the program. The shadowed variables are not accessible in the @@ -17108,7 +17352,7 @@ function. When this happens, we say the function is @dfn{recursive}. The act of a function calling itself is called @dfn{recursion}. All the built-in functions return a value to their caller. -User-defined functions can do also, using the @code{return} statement, +User-defined functions can do so also, using the @code{return} statement, which is described in detail in @ref{Return Statement}. Many of the subsequent examples in this @value{SECTION} use the @code{return} statement. @@ -17146,6 +17390,7 @@ keyword @code{function} when defining a function. @node Function Example @subsection Function Definition Examples +@cindex function definition example Here is an example of a user-defined function, called @code{myprint()}, that takes a number and prints it in a specific format: @@ -17200,7 +17445,8 @@ Instead of having to repeat this loop everywhere that you need to clear out an array, your program can just call @code{delarray}. (This guarantees portability. The use of @samp{delete @var{array}} to delete -the contents of an entire array is a nonstandard extension.) +the contents of an entire array is a recent@footnote{Late in 2012.} +addition to the POSIX standard.) The following is an example of a recursive function. It takes a string as an input parameter and returns the string in backwards order. @@ -17256,7 +17502,10 @@ function ctime(ts, format) @subsection Calling User-Defined Functions @c STARTOFRANGE fudc -This section describes how to call a user-defined function. +@cindex functions, user-defined, calling +@dfn{Calling a function} means causing the function to run and do its job. +A function call is an expression and its value is the value returned by +the function. @menu * Calling A Function:: Don't use spaces. @@ -17267,11 +17516,6 @@ This section describes how to call a user-defined function. @node Calling A Function @subsubsection Writing A Function Call -@cindex functions, user-defined, calling -@dfn{Calling a function} means causing the function to run and do its job. -A function call is an expression and its value is the value returned by -the function. - A function call consists of the function name followed by the arguments in parentheses. @command{awk} expressions are what you write in the call for the arguments. Each time the call is executed, these @@ -17295,8 +17539,8 @@ an error. @node Variable Scope @subsubsection Controlling Variable Scope -@cindex local variables -@cindex variables, local +@cindex local variables, in a function +@cindex variables, local to a function There is no way to make a variable local to a @code{@{ @dots{} @}} block in @command{awk}, but you can make a variable local to a function. It is good practice to do so whenever a variable is needed only in that @@ -17741,7 +17985,7 @@ character: @example the_func = "sum" -result = @@the_func() # calls the `sum' function +result = @@the_func() # calls the sum() function @end example Here is a full program that processes the previously shown data, @@ -17862,8 +18106,9 @@ We can do something similar using @command{gawk}, like this: @ignore @c file eg/lib/quicksort.awk # -# Arnold Robbins, arnold@skeeve.com, Public Domain +# Arnold Robbins, arnold@@skeeve.com, Public Domain # January 2009 + @c endfile @end ignore @@ -17936,7 +18181,7 @@ or equal to), which yields data sorted in descending order. Next comes a sorting function. It is parameterized with the starting and ending field numbers and the comparison function. It builds an array with -the data and calls @code{quicksort} appropriately, and then formats the +the data and calls @code{quicksort()} appropriately, and then formats the results as a single string: @example @@ -18074,6 +18319,8 @@ it allows you to encapsulate algorithms and program tasks in a single place. It simplifies programming, making program development more manageable, and making programs more readable. +@cindex Kernighan, Brian +@cindex Plauger, P.J.@: In their seminal 1976 book, @cite{Software Tools},@footnote{Sadly, over 35 years later, many of the lessons taught by this book have yet to be learned by a vast number of practicing programmers.} Brian Kernighan @@ -18203,7 +18450,7 @@ with the user's program. @cindex underscore (@code{_}), in names of private variables In addition, several of the library functions use a prefix that helps indicate what function or set of functions use the variables---for example, -@code{_pw_byname} in the user database routines +@code{_pw_byname()} in the user database routines (@pxref{Passwd Functions}). This convention is recommended, since it even further decreases the chance of inadvertent conflict among variable names. Note that this @@ -18222,7 +18469,7 @@ The leading capital letter indicates that it is global, while the fact that the variable name is not all capital letters indicates that the variable is not one of @command{awk}'s built-in variables, such as @code{FS}. -@cindex @option{--dump-variables} option +@cindex @option{--dump-variables} option, using for library functions It is also important that @emph{all} variables in library functions that do not need to save state are, in fact, declared local.@footnote{@command{gawk}'s @option{--dump-variables} command-line @@ -18517,9 +18764,9 @@ with an @code{exit} statement. The way @code{printf} and @code{sprintf()} (@pxref{Printf}) perform rounding often depends upon the system's C @code{sprintf()} -subroutine. On many machines, @code{sprintf()} rounding is ``unbiased,'' -which means it doesn't always round a trailing @samp{.5} up, contrary -to naive expectations. In unbiased rounding, @samp{.5} rounds to even, +subroutine. On many machines, @code{sprintf()} rounding is @dfn{unbiased}, +which means it doesn't always round a trailing .5 up, contrary +to naive expectations. In unbiased rounding, .5 rounds to even, rather than always up, so 1.5 rounds to 2 but 4.5 rounds to 4. This means that if you are using a format that does rounding (e.g., @code{"%.0f"}), you should check what your system does. The following function does @@ -18568,7 +18815,7 @@ function round(x, ival, aval, fraction) @c don't include test harness in the file that gets installed # test harness -@{ print $0, round($0) @} +# @{ print $0, round($0) @} @end example @node Cliff Random Function @@ -18635,6 +18882,7 @@ reason to build them into the @command{awk} interpreter: @cindex @code{ord()} user-defined function @cindex @code{chr()} user-defined function +@cindex @code{_ord_init()} user-defined function @example @c file eg/lib/ord.awk # ord.awk --- do ord and chr @@ -18681,8 +18929,9 @@ function _ord_init( low, high, i, t) @cindex character sets (machine character encodings) @cindex ASCII @cindex EBCDIC +@cindex Unicode @cindex mark parity -Some explanation of the numbers used by @code{chr()} is worthwhile. +Some explanation of the numbers used by @code{_ord_init()} is worthwhile. The most prominent character set in use today is ASCII.@footnote{This is changing; many systems use Unicode, a very large character set that includes ASCII as a subset. On systems with full Unicode support, @@ -18693,7 +18942,7 @@ Although an defines characters that use the values from 0 to 127.@footnote{ASCII has been extended in many countries to use the values from 128 to 255 for country-specific characters. If your system uses these extensions, -you can simplify @code{_ord_init} to loop from 0 to 255.} +you can simplify @code{_ord_init()} to loop from 0 to 255.} In the now distant past, at least one minicomputer manufacturer @c Pr1me, blech @@ -19338,7 +19587,7 @@ END @{ Occasionally, you might not want @command{awk} to process command-line variable assignments (@pxref{Assignment Options}). -In particular, if you have a file name that contain an @samp{=} character, +In particular, if you have a file name that contains an @samp{=} character, @command{awk} treats the file name as an assignment, and does not process it. Some users have suggested an additional command-line option for @command{gawk} @@ -20008,7 +20257,7 @@ from anywhere within a user's program, and the user may have his or her own way of splitting records and fields. -@cindex @code{PROCINFO} array +@cindex @code{PROCINFO} array, testing the field splitting The @code{using_fw} variable checks @code{PROCINFO["FS"]}, which is @code{"FIELDWIDTHS"} if field splitting is being done with @code{FIELDWIDTHS}. This makes it possible to restore the correct @@ -20017,7 +20266,7 @@ field-splitting mechanism later. The test can only be true for or on some other @command{awk} implementation. The code that checks for using @code{FPAT}, using @code{using_fpat} -and @code{PROCINFO["FS"]} is similar. +and @code{PROCINFO["FS"]}, is similar. The main part of the function uses a loop to read database lines, split the line into fields, and then store the line into each array as necessary. @@ -20047,10 +20296,9 @@ function getpwnam(name) @end example @cindex @code{getpwuid()} function (C library) -Similarly, -the @code{getpwuid} function takes a user ID number argument. If that -user number is in the database, it returns the appropriate line. Otherwise, it -returns the null string: +Similarly, the @code{getpwuid()} function takes a user ID number +argument. If that user number is in the database, it returns the +appropriate line. Otherwise, it returns the null string: @cindex @code{getpwuid()} user-defined function @example @@ -20132,7 +20380,7 @@ uses these functions. @cindex group database, reading @c STARTOFRANGE datagr @cindex database, group, reading -@cindex @code{PROCINFO} array +@cindex @code{PROCINFO} array, and group membership @cindex @code{getgrent()} function (C library) @cindex @code{getgrent()} user-defined function @cindex groups@comma{} information about @@ -20554,7 +20802,7 @@ index and value, use the indirect function call syntax and the value. When calling @code{walk_array()}, you would pass the name of a user-defined -function that expects to receive and index and a value, and then processes +function that expects to receive an index and a value, and then processes the element. @@ -20908,7 +21156,7 @@ complete field list, including filler fields: @example @c file eg/prog/cut.awk -function set_charlist( field, i, j, f, g, t, +function set_charlist( field, i, j, f, g, n, m, t, filler, last, len) @{ field = 1 # count total fields @@ -21005,6 +21253,7 @@ of picking the input line apart by characters. @cindex searching, files for regular expressions @c STARTOFRANGE fsregexp @cindex files, searching for regular expressions +@c STARTOFRANGE egrep @cindex @command{egrep} utility The @command{egrep} utility searches files for patterns. It uses regular expressions that are almost identical to those available in @command{awk} @@ -21290,12 +21539,14 @@ or not. @c ENDOFRANGE regexps @c ENDOFRANGE sfregexp @c ENDOFRANGE fsregexp +@c ENDOFRANGE egrep @node Id Program @subsection Printing out User Information @cindex printing, user information @cindex users, information about, printing +@c STARTOFRANGE id @cindex @command{id} utility The @command{id} utility lists a user's real and effective user ID numbers, real and effective group ID numbers, and the user's group set, if any. @@ -21308,7 +21559,7 @@ $ @kbd{id} @print{} uid=500(arnold) gid=500(arnold) groups=6(disk),7(lp),19(floppy) @end example -@cindex @code{PROCINFO} array +@cindex @code{PROCINFO} array, and user and group ID numbers This information is part of what is provided by @command{gawk}'s @code{PROCINFO} array (@pxref{Built-in Variables}). However, the @command{id} utility provides a more palatable output than just @@ -21409,7 +21660,6 @@ BEGIN \ @c endfile @end example -@cindex @code{in} operator The test in the @code{for} loop is worth noting. Any supplementary groups in the @code{PROCINFO} array have the indices @code{"group1"} through @code{"group@var{N}"} for some @@ -21419,7 +21669,7 @@ there are. This loop works by starting at one, concatenating the value with @code{"group"}, and then using @code{in} to see if that value is -in the array. Eventually, @code{i} is incremented past +in the array (@pxref{Reference to Elements}). Eventually, @code{i} is incremented past the last group in the array and the loop exits. The loop is also correct if there are @emph{no} supplementary @@ -21432,6 +21682,7 @@ The POSIX version of @command{id} takes arguments that control which information is printed. Modify this version to accept the same arguments and perform in the same way. @end ignore +@c ENDOFRANGE id @node Split Program @subsection Splitting a Large File into Pieces @@ -21440,6 +21691,7 @@ arguments and perform in the same way. @c STARTOFRANGE filspl @cindex files, splitting +@c STARTOFRANGE split @cindex @code{split} utility The @command{split} program splits large text files into smaller pieces. Usage is as follows:@footnote{This is the traditional usage. The @@ -21583,12 +21835,14 @@ which isn't true for EBCDIC systems. @c Exercise: Fix these problems. @c BFD... @c ENDOFRANGE filspl +@c ENDOFRANGE split @node Tee Program @subsection Duplicating Output into Multiple Files @cindex files, multiple@comma{} duplicating output into @cindex output, duplicating into files +@c STARTOFRANGE tee @cindex @code{tee} utility The @code{tee} program is known as a ``pipe fitting.'' @code{tee} copies its standard input to its standard output and also duplicates it to the @@ -21703,6 +21957,7 @@ END \ @} @c endfile @end example +@c ENDOFRANGE tee @node Uniq Program @subsection Printing Nonduplicated Lines of Text @@ -21713,6 +21968,7 @@ END \ @cindex printing, unduplicated lines of text @c STARTOFRANGE tpul @cindex text@comma{} printing, unduplicated lines of +@c STARTOFRANGE uniq @cindex @command{uniq} utility The @command{uniq} utility reads sorted lines of data on its standard input, and by default removes duplicate lines. In other words, it only @@ -21964,6 +22220,7 @@ END @{ @end example @c ENDOFRANGE prunt @c ENDOFRANGE tpul +@c ENDOFRANGE uniq @node Wc Program @subsection Counting Things @@ -21980,6 +22237,7 @@ END @{ @cindex characters, counting @c STARTOFRANGE lico @cindex lines, counting +@c STARTOFRANGE wc @cindex @command{wc} utility The @command{wc} (word count) utility counts lines, words, and characters in one or more input files. Its usage is as follows: @@ -22162,6 +22420,7 @@ END @{ @c ENDOFRANGE lico @c ENDOFRANGE woco @c ENDOFRANGE chco +@c ENDOFRANGE wc @c ENDOFRANGE posimawk @node Miscellaneous Programs @@ -22456,6 +22715,7 @@ seconds are necessary: @c STARTOFRANGE chtra @cindex characters, transliterating +@c STARTOFRANGE tr @cindex @command{tr} utility The system @command{tr} utility transliterates characters. For example, it is often used to map uppercase letters into lowercase for further processing: @@ -22604,6 +22864,7 @@ An obvious improvement to this program would be to set up the assumes that the ``from'' and ``to'' lists will never change throughout the lifetime of the program. @c ENDOFRANGE chtra +@c ENDOFRANGE tr @node Labels Program @subsection Printing Mailing Labels @@ -22663,6 +22924,7 @@ that there are two blank lines at the top and two blank lines at the bottom. The @code{END} rule arranges to flush the final page of labels; there may not have been an even multiple of 20 labels in the data: +@c STARTOFRANGE labels @cindex @code{labels.awk} program @example @c file eg/prog/labels.awk @@ -22730,6 +22992,7 @@ END \ @end example @c ENDOFRANGE prml @c ENDOFRANGE mlprint +@c ENDOFRANGE labels @node Word Sorting @subsection Generating Word-Usage Counts @@ -22796,6 +23059,7 @@ to remove punctuation characters. Finally, we solve the third problem by using the system @command{sort} utility to process the output of the @command{awk} script. Here is the new version of the program: +@c STARTOFRANGE wordfreq @cindex @code{wordfreq.awk} program @example @c file eg/prog/wordfreq.awk @@ -22857,6 +23121,7 @@ have true pipes at the command-line (or batch-file) level. See the general operating system documentation for more information on how to use the @command{sort} program. @c ENDOFRANGE worus +@c ENDOFRANGE wordfreq @node History Sorting @subsection Removing Duplicates from Unsorted Text @@ -22886,6 +23151,7 @@ Each element of @code{lines} is a unique command, and the indices of The @code{END} rule simply prints out the lines, in order: @cindex Rakitzis, Byron +@c STARTOFRANGE histsort @cindex @code{histsort.awk} program @example @c file eg/prog/histsort.awk @@ -22928,6 +23194,7 @@ print data[lines[i]], lines[i] This works because @code{data[$0]} is incremented each time a line is seen. @c ENDOFRANGE lidu +@c ENDOFRANGE histsort @node Extract Program @subsection Extracting Programs from Texinfo Source Files @@ -23038,6 +23305,7 @@ The first rule handles calling @code{system()}, checking that a command is given (@code{NF} is at least three) and also checking that the command exits with a zero exit status, signifying OK: +@c STARTOFRANGE extract @cindex @code{extract.awk} program @example @c file eg/prog/extract.awk @@ -23196,6 +23464,7 @@ END @{ @end example @c ENDOFRANGE texse @c ENDOFRANGE fitex +@c ENDOFRANGE extract @node Simple Sed @subsection A Simple Stream Editor @@ -23225,6 +23494,7 @@ additional arguments are treated as data file names to process. If none are provided, the standard input is used: @cindex Brennan, Michael +@c STARTOFRANGE awksed @cindex @command{awksed.awk} program @c @cindex simple stream editor @c @cindex stream editor, simple @@ -23321,6 +23591,7 @@ Exercise: what are the advantages and disadvantages of this version versus sed? Others? @end ignore +@c ENDOFRANGE awksed @node Igawk Program @subsection An Easy Way to Use Library Functions @@ -23464,6 +23735,7 @@ program. The program is as follows: +@c STARTOFRANGE igawk @cindex @code{igawk.sh} program @example @c file eg/prog/igawk.sh @@ -23636,7 +23908,7 @@ BEGIN @{ @c endfile @end example -The stack is initialized with @code{ARGV[1]}, which will be @file{/dev/stdin}. +The stack is initialized with @code{ARGV[1]}, which will be @samp{/dev/stdin}. The main loop comes next. Input lines are read in succession. Lines that do not start with @samp{@@include} are printed verbatim. If the line does start with @samp{@@include}, the file name is in @code{$2}. @@ -23823,10 +24095,12 @@ statements for the desired library functions. @c ENDOFRANGE libfex @c ENDOFRANGE flibex @c ENDOFRANGE awkpex +@c ENDOFRANGE igawk @node Anagram Program @subsection Finding Anagrams From A Dictionary +@cindex anagrams, finding An interesting programming challenge is to search for @dfn{anagrams} in a word list (such as @@ -23846,6 +24120,7 @@ The following program uses arrays of arrays to bring together words with the same signature and array sorting to print the words in sorted order. +@c STARTOFRANGE anagram @cindex @code{anagram.awk} program @example @c file eg/prog/anagram.awk @@ -23953,10 +24228,13 @@ babels beslab babery yabber @dots{} @end example +@c ENDOFRANGE anagram @node Signature Program @subsection And Now For Something Completely Different +@cindex signature program +@cindex Brini, Davide The following program was written by Davide Brini @c (@email{dave_br@@gmx.com}) and is published on @uref{http://backreference.org/2011/02/03/obfuscated-awk/, @@ -24088,12 +24366,15 @@ It contains the following chapters: @item @ref{Dynamic Extensions}. +@end itemize @end ifdocbook @end ignore @node Advanced Features @chapter Advanced Features of @command{gawk} +@ifset WITH_NETWORK_CHAPTER @cindex advanced features, network connections, See Also networks@comma{} connections +@end ifset @c STARTOFRANGE gawadv @cindex @command{gawk}, features, advanced @c STARTOFRANGE advgaw @@ -24500,9 +24781,9 @@ sorted array traversal is not the default. @subsection Sorting Array Values and Indices with @command{gawk} @cindex arrays, sorting -@cindex @code{asort()} function (@command{gawk}) +@cindexgawkfunc{asort} @cindex @code{asort()} function (@command{gawk}), arrays@comma{} sorting -@cindex @code{asorti()} function (@command{gawk}) +@cindexgawkfunc{asorti} @cindex @code{asorti()} function (@command{gawk}), arrays@comma{} sorting @cindex sort function, arrays, sorting In most @command{awk} implementations, sorting an array requires writing @@ -24597,9 +24878,8 @@ both arrays use the values. @c Document It And Call It A Feature. Sigh. @cindex @command{gawk}, @code{IGNORECASE} variable in -@cindex @code{IGNORECASE} variable -@cindex arrays, sorting, @code{IGNORECASE} variable and -@cindex @code{IGNORECASE} variable, array sorting and +@cindex arrays, sorting, and @code{IGNORECASE} variable +@cindex @code{IGNORECASE} variable, and array sorting functions Because @code{IGNORECASE} affects string comparisons, the value of @code{IGNORECASE} also affects sorting for both @code{asort()} and @code{asorti()}. Note also that the locale's sorting order does @emph{not} @@ -24678,7 +24958,7 @@ open a @emph{two-way} pipe to another process. The second process is termed a @dfn{coprocess}, since it runs in parallel with @command{gawk}. The two-way connection is created using the @samp{|&} operator (borrowed from the Korn shell, @command{ksh}):@footnote{This is very -different from the same operator in the C shell.} +different from the same operator in the C shell and in Bash.} @example do @{ @@ -24768,7 +25048,7 @@ As a side note, the assignment @samp{LC_ALL=C} in the @command{sort} command ensures traditional Unix (ASCII) sorting from @command{sort}. @cindex @command{gawk}, @code{PROCINFO} array in -@cindex @code{PROCINFO} array +@cindex @code{PROCINFO} array, and communications via ptys You may also use pseudo-ttys (ptys) for two-way communication instead of pipes, if your system supports them. This is done on a per-command basis, by setting a special element @@ -24966,52 +25246,60 @@ foo junk @end example -Here is the @file{awkprof.out} that results from running the @command{gawk} -profiler on this program and data (this example also illustrates that @command{awk} -programmers sometimes have to work late): +Here is the @file{awkprof.out} that results from running the +@command{gawk} profiler on this program and data. (This example also +illustrates that @command{awk} programmers sometimes get up very early +in the morning to work.) -@cindex @code{BEGIN} pattern -@cindex @code{END} pattern +@cindex @code{BEGIN} pattern, and profiling +@cindex @code{END} pattern, and profiling @example - # gawk profile, created Sun Aug 13 00:00:15 2000 + # gawk profile, created Thu Feb 27 05:16:21 2014 - # BEGIN block(s) + # BEGIN block(s) - BEGIN @{ - 1 print "First BEGIN rule" - 1 print "Second BEGIN rule" - @} + BEGIN @{ + 1 print "First BEGIN rule" + @} - # Rule(s) + BEGIN @{ + 1 print "Second BEGIN rule" + @} - 5 /foo/ @{ # 2 - 2 print "matched /foo/, gosh" - 6 for (i = 1; i <= 3; i++) @{ - 6 sing() - @} - @} + # Rule(s) - 5 @{ - 5 if (/foo/) @{ # 2 - 2 print "if is true" - 3 @} else @{ - 3 print "else is true" - @} - @} + 5 /foo/ @{ # 2 + 2 print "matched /foo/, gosh" + 6 for (i = 1; i <= 3; i++) @{ + 6 sing() + @} + @} - # END block(s) + 5 @{ + 5 if (/foo/) @{ # 2 + 2 print "if is true" + 3 @} else @{ + 3 print "else is true" + @} + @} - END @{ - 1 print "First END rule" - 1 print "Second END rule" - @} + # END block(s) - # Functions, listed alphabetically + END @{ + 1 print "First END rule" + @} - 6 function sing(dummy) - @{ - 6 print "I gotta be me!" - @} + END @{ + 1 print "Second END rule" + @} + + + # Functions, listed alphabetically + + 6 function sing(dummy) + @{ + 6 print "I gotta be me!" + @} @end example This example illustrates many of the basic features of profiling output. @@ -25019,15 +25307,16 @@ They are as follows: @itemize @bullet @item -The program is printed in the order @code{BEGIN} rule, -@code{BEGINFILE} rule, +The program is printed in the order @code{BEGIN} rules, +@code{BEGINFILE} rules, pattern/action rules, -@code{ENDFILE} rule, @code{END} rule and functions, listed +@code{ENDFILE} rules, @code{END} rules and functions, listed alphabetically. -Multiple @code{BEGIN} and @code{END} rules are merged together, -as are multiple @code{BEGINFILE} and @code{ENDFILE} rules. +Multiple @code{BEGIN} and @code{END} rules retain their +separate identities, as do +multiple @code{BEGINFILE} and @code{ENDFILE} rules. -@cindex patterns, counts +@cindex patterns, counts, in a profile @item Pattern-action rules have two counts. The first count, to the left of the rule, shows how many times @@ -25047,7 +25336,7 @@ is a count showing how many times the condition was true. The count for the @code{else} indicates how many times the test failed. -@cindex loops, count for header +@cindex loops, count for header, in a profile @item The count for a loop header (such as @code{for} or @code{while}) shows how many times the loop test was executed. @@ -25055,8 +25344,8 @@ or @code{while}) shows how many times the loop test was executed. statement in a rule to determine how many times the rule was executed. If the first statement is a loop, the count is misleading.) -@cindex functions, user-defined, counts -@cindex user-defined, functions, counts +@cindex functions, user-defined, counts, in a profile +@cindex user-defined, functions, counts, in a profile @item For user-defined functions, the count next to the @code{function} keyword indicates how many times the function was called. @@ -25070,8 +25359,8 @@ The layout uses ``K&R'' style with TABs. Braces are used everywhere, even when the body of an @code{if}, @code{else}, or loop is only a single statement. -@cindex @code{()} (parentheses) -@cindex parentheses @code{()} +@cindex @code{()} (parentheses), in a profile +@cindex parentheses @code{()}, in a profile @item Parentheses are used only where needed, as indicated by the structure of the program and the precedence rules. @@ -25106,8 +25395,8 @@ typed when you wrote it. This is because @command{gawk} creates the profiled version by ``pretty printing'' its internal representation of the program. The advantage to this is that @command{gawk} can produce a standard representation. The disadvantage is that all source-code -comments are lost, as are the distinctions among multiple @code{BEGIN}, -@code{END}, @code{BEGINFILE}, and @code{ENDFILE} rules. Also, things such as: +comments are lost. +Also, things such as: @example /foo/ @@ -25127,6 +25416,7 @@ which is correct, but possibly surprising. @cindex profiling @command{awk} programs, dynamically @cindex @command{gawk} program, dynamic profiling +@cindex dynamic profiling Besides creating profiles when a program has completed, @command{gawk} can produce a profile while it is running. This is useful if your @command{awk} program goes into an @@ -25140,9 +25430,9 @@ $ @kbd{gawk --profile -f myprog &} @end example @cindex @command{kill} command@comma{} dynamic profiling -@cindex @code{USR1} signal -@cindex @code{SIGUSR1} signal -@cindex signals, @code{USR1}/@code{SIGUSR1} +@cindex @code{USR1} signal, for dynamic profiling +@cindex @code{SIGUSR1} signal, for dynamic profiling +@cindex signals, @code{USR1}/@code{SIGUSR1}, for profiling @noindent The shell prints a job number and process ID number; in this case, 13992. Use the @command{kill} command to send the @code{USR1} signal @@ -25173,9 +25463,9 @@ You may send @command{gawk} the @code{USR1} signal as many times as you like. Each time, the profile and function call trace are appended to the output profile file. -@cindex @code{HUP} signal -@cindex @code{SIGHUP} signal -@cindex signals, @code{HUP}/@code{SIGHUP} +@cindex @code{HUP} signal, for dynamic profiling +@cindex @code{SIGHUP} signal, for dynamic profiling +@cindex signals, @code{HUP}/@code{SIGHUP}, for profiling If you use the @code{HUP} signal instead of the @code{USR1} signal, @command{gawk} produces the profile and the function call trace and then exits. @@ -25197,6 +25487,11 @@ keyboard. The @code{INT} signal is generated by the Finally, @command{gawk} also accepts another option, @option{--pretty-print}. When called this way, @command{gawk} ``pretty prints'' the program into @file{awkprof.out}, without any execution counts. + +@quotation NOTE +The @option{--pretty-print} option still runs your program. +This will change in the next major release. +@end quotation @c ENDOFRANGE advgaw @c ENDOFRANGE gawadv @c ENDOFRANGE awkp @@ -25308,6 +25603,7 @@ lookup of the translations. @cindex @code{.po} files @cindex files, @code{.po} +@c STARTOFRANGE portobfi @cindex portable object files @cindex files, portable object @item @@ -25319,6 +25615,7 @@ For example, there might be a @file{fr.po} for a French translation. @cindex @code{.gmo} files @cindex files, @code{.gmo} @cindex message object files +@c STARTOFRANGE portmsgfi @cindex files, message object @item Each language's @file{.po} file is converted into a binary @@ -25466,7 +25763,7 @@ String constants marked with a leading underscore are candidates for translation at runtime. String constants without a leading underscore are not translated. -@cindex @code{dcgettext()} function (@command{gawk}) +@cindexgawkfunc{dcgettext} @item dcgettext(@var{string} @r{[}, @var{domain} @r{[}, @var{category}@r{]]}) Return the translation of @var{string} in text domain @var{domain} for locale category @var{category}. @@ -25492,7 +25789,7 @@ chosen to be simple and to allow for reasonable @command{awk}-style default arguments. @end quotation -@cindex @code{dcngettext()} function (@command{gawk}) +@cindexgawkfunc{dcngettext} @item dcngettext(@var{string1}, @var{string2}, @var{number} @r{[}, @var{domain} @r{[}, @var{category}@r{]]}) Return the plural form used for @var{number} of the translation of @var{string1} and @var{string2} in text domain @@ -25508,7 +25805,7 @@ The same remarks about argument order as for the @code{dcgettext()} function app @cindex files, @code{.gmo}, specifying directory of @cindex message object files, specifying directory of @cindex files, message object, specifying directory of -@cindex @code{bindtextdomain()} function (@command{gawk}) +@cindexgawkfunc{bindtextdomain} @item bindtextdomain(@var{directory} @r{[}, @var{domain}@r{]}) Change the directory in which @code{gettext} looks for @file{.gmo} files, in case they @@ -25610,7 +25907,7 @@ and use translations from @command{awk}. @cindex portable object files @cindex files, portable object Once a program's translatable strings have been marked, they must -be extracted to create the initial @file{.po} file. +be extracted to create the initial @file{.pot} file. As part of translation, it is often helpful to rearrange the order in which arguments to @code{printf} are output. @@ -25659,6 +25956,8 @@ second argument to @code{dcngettext()}.@footnote{The @xref{I18N Example}, for the full list of steps to go through to create and test translations for @command{guide}. +@c ENDOFRANGE portobfi +@c ENDOFRANGE portmsgfi @node Printf Ordering @subsection Rearranging @code{printf} Arguments @@ -25705,7 +26004,7 @@ example, @samp{string} is the first argument and @samp{length(string)} is the se @example $ @kbd{gawk 'BEGIN @{} > @kbd{string = "Dont Panic"} -> @kbd{printf _"%2$d characters live in \"%1$s\"\n",} +> @kbd{printf "%2$d characters live in \"%1$s\"\n",} > @kbd{string, length(string)} > @kbd{@}'} @print{} 10 characters live in "Dont Panic" @@ -25739,7 +26038,7 @@ This is somewhat counterintuitive. and those with positional specifiers in the same string: @example -$ @kbd{gawk 'BEGIN @{ printf _"%d %3$s\n", 1, 2, "hi" @}'} +$ @kbd{gawk 'BEGIN @{ printf "%d %3$s\n", 1, 2, "hi" @}'} @error{} gawk: cmd. line:1: fatal: must use `count$' on all formats or none @end example @@ -26080,6 +26379,7 @@ The following list defines terms used throughout the rest of this @value{CHAPTER}. @table @dfn +@cindex stack frame @item Stack Frame Programs generally call functions during the course of their execution. One function can call another, or a function can call itself (recursion). @@ -26101,6 +26401,7 @@ invoked. Commands that print the call stack print information about each stack frame (as detailed later on). @item Breakpoint +@cindex breakpoint During debugging, you often wish to let the program run until it reaches a certain point, and then continue execution from there one statement (or instruction) at a time. The way to do this is to set @@ -26110,6 +26411,7 @@ take over control of the program's execution. You can add and remove as many breakpoints as you like. @item Watchpoint +@cindex watchpoint A watchpoint is similar to a breakpoint. The difference is that breakpoints are oriented around the code: stop when a certain point in the code is reached. A watchpoint, however, specifies that program execution @@ -26141,6 +26443,7 @@ by the higher-level @command{awk} commands. @node Sample Debugging Session @section Sample Debugging Session +@cindex sample debugging session In order to illustrate the use of @command{gawk} as a debugger, let's look at a sample debugging session. We will use the @command{awk} implementation of the @@ -26154,13 +26457,16 @@ as our example. @node Debugger Invocation @subsection How to Start the Debugger +@cindex starting the debugger +@cindex debugger, how to start -Starting the debugger is almost exactly like running @command{awk}, except you have to -pass an additional option @option{--debug} or the corresponding short option @option{-D}. -The file(s) containing the program and any supporting code are given on the command -line as arguments to one or more @option{-f} options. (@command{gawk} is not designed -to debug command-line programs, only programs contained in files.) In our case, -we invoke the debugger like this: +Starting the debugger is almost exactly like running @command{gawk}, +except you have to pass an additional option @option{--debug} or the +corresponding short option @option{-D}. The file(s) containing the +program and any supporting code are given on the command line as arguments +to one or more @option{-f} options. (@command{gawk} is not designed +to debug command-line programs, only programs contained in files.) +In our case, we invoke the debugger like this: @example $ @kbd{gawk -D -f getopt.awk -f join.awk -f uniq.awk inputfile} @@ -26293,7 +26599,7 @@ gawk> @kbd{p NR} @noindent So we can see that @code{are_equal()} was only called for the second record -of the file. Of course, this is because our program contained a rule for +of the file. Of course, this is because our program contains a rule for @samp{NR == 1}: @example @@ -26493,21 +26799,24 @@ controlling breakpoints are: @cindex debugger commands, @code{break} @cindex @code{break} debugger command @cindex @code{b} debugger command (alias for @code{break}) +@cindex set breakpoint +@cindex breakpoint, setting @item @code{break} [[@var{filename}@code{:}]@var{n} | @var{function}] [@code{"@var{expression}"}] @itemx @code{b} [[@var{filename}@code{:}]@var{n} | @var{function}] [@code{"@var{expression}"}] Without any argument, set a breakpoint at the next instruction to be executed in the selected stack frame. Arguments can be one of the following: +@c @asis for docbook @c nested table -@table @var -@item n +@table @asis +@item @var{n} Set a breakpoint at line number @var{n} in the current source file. -@item filename@code{:}n +@item @var{filename}@code{:}@var{n} Set a breakpoint at line number @var{n} in source file @var{filename}. -@item function +@item @var{function} Set a breakpoint at entry to (the first instruction of) function @var{function}. @end table @@ -26523,6 +26832,8 @@ it continues executing the program. @cindex debugger commands, @code{clear} @cindex @code{clear} debugger command +@cindex delete breakpoint at location +@cindex breakpoint at location, how to delete @item @code{clear} [[@var{filename}@code{:}]@var{n} | @var{function}] Without any argument, delete any breakpoint at the next instruction to be executed in the selected stack frame. If the program stops at @@ -26530,19 +26841,20 @@ a breakpoint, this deletes that breakpoint so that the program does not stop at that location again. Arguments can be one of the following: @c nested table -@table @var -@item n +@table @asis +@item @var{n} Delete breakpoint(s) set at line number @var{n} in the current source file. -@item filename@code{:}n +@item @var{filename}@code{:}@var{n} Delete breakpoint(s) set at line number @var{n} in source file @var{filename}. -@item function +@item @var{function} Delete breakpoint(s) set at entry to function @var{function}. @end table @cindex debugger commands, @code{condition} @cindex @code{condition} debugger command +@cindex breakpoint condition @item @code{condition} @var{n} @code{"@var{expression}"} Add a condition to existing breakpoint or watchpoint @var{n}. The condition is an @command{awk} expression that the debugger evaluates @@ -26556,6 +26868,8 @@ watchpoint is made unconditional. @cindex debugger commands, @code{delete} @cindex @code{delete} debugger command @cindex @code{d} debugger command (alias for @code{delete}) +@cindex delete breakpoint by number +@cindex breakpoint, delete by number @item @code{delete} [@var{n1 n2} @dots{}] [@var{n}--@var{m}] @itemx @code{d} [@var{n1 n2} @dots{}] [@var{n}--@var{m}] Delete specified breakpoints or a range of breakpoints. Deletes @@ -26563,6 +26877,8 @@ all defined breakpoints if no argument is supplied. @cindex debugger commands, @code{disable} @cindex @code{disable} debugger command +@cindex disable breakpoint +@cindex breakpoint, how to disable or enable @item @code{disable} [@var{n1 n2} @dots{} | @var{n}--@var{m}] Disable specified breakpoints or a range of breakpoints. Without any argument, disables all breakpoints. @@ -26571,6 +26887,7 @@ any argument, disables all breakpoints. @cindex debugger commands, @code{enable} @cindex @code{enable} debugger command @cindex @code{e} debugger command (alias for @code{enable}) +@cindex enable breakpoint @item @code{enable} [@code{del} | @code{once}] [@var{n1 n2} @dots{}] [@var{n}--@var{m}] @itemx @code{e} [@code{del} | @code{once}] [@var{n1 n2} @dots{}] [@var{n}--@var{m}] Enable specified breakpoints or a range of breakpoints. Without @@ -26590,6 +26907,7 @@ the program stops at the breakpoint. @cindex debugger commands, @code{ignore} @cindex @code{ignore} debugger command +@cindex ignore breakpoint @item @code{ignore} @var{n} @var{count} Ignore breakpoint number @var{n} the next @var{count} times it is hit. @@ -26598,6 +26916,7 @@ hit. @cindex debugger commands, @code{tbreak} @cindex @code{tbreak} debugger command @cindex @code{t} debugger command (alias for @code{tbreak}) +@cindex temporary breakpoint @item @code{tbreak} [[@var{filename}@code{:}]@var{n} | @var{function}] @itemx @code{t} [[@var{filename}@code{:}]@var{n} | @var{function}] Set a temporary breakpoint (enabled for only one stop). @@ -26618,6 +26937,8 @@ execution of the program than we saw in our earlier example: @cindex @code{silent} debugger command @cindex debugger commands, @code{end} @cindex @code{end} debugger command +@cindex breakpoint commands +@cindex commands to execute at breakpoint @item @code{commands} [@var{n}] @itemx @code{silent} @itemx @dots{} @@ -26645,6 +26966,7 @@ gawk> @cindex debugger commands, @code{c} (@code{continue}) @cindex debugger commands, @code{continue} +@cindex continue program, in debugger @item @code{continue} [@var{count}] @itemx @code{c} [@var{count}] Resume program execution. If continued from a breakpoint and @var{count} is @@ -26661,6 +26983,7 @@ Print the returned value. @cindex debugger commands, @code{next} @cindex @code{next} debugger command @cindex @code{n} debugger command (alias for @code{next}) +@cindex single-step execution, in the debugger @item @code{next} [@var{count}] @itemx @code{n} [@var{count}] Continue execution to the next source line, stepping over function calls. @@ -26755,6 +27078,7 @@ items on the list. @cindex debugger commands, @code{eval} @cindex @code{eval} debugger command +@cindex evaluate expressions, in debugger @item @code{eval "@var{awk statements}"} Evaluate @var{awk statements} in the context of the running program. You can do anything that an @command{awk} program would do: assign @@ -26772,6 +27096,7 @@ parameters defined by the program. @cindex debugger commands, @code{print} @cindex @code{print} debugger command @cindex @code{p} debugger command (alias for @code{print}) +@cindex print variables, in debugger @item @code{print} @var{var1}[@code{,} @var{var2} @dots{}] @itemx @code{p} @var{var1}[@code{,} @var{var2} @dots{}] Print the value of a @command{gawk} variable or field. @@ -26805,6 +27130,7 @@ No newline is printed unless one is specified. @cindex debugger commands, @code{set} @cindex @code{set} debugger command +@cindex assign values to variables, in debugger @item @code{set} @var{var}@code{=}@var{value} Assign a constant (number or string) value to an @command{awk} variable or field. @@ -26817,6 +27143,7 @@ You can also set special @command{awk} variables, such as @code{FS}, @cindex debugger commands, @code{watch} @cindex @code{watch} debugger command @cindex @code{w} debugger command (alias for @code{watch}) +@cindex set watchpoint @item @code{watch} @var{var} | @code{$}@var{n} [@code{"@var{expression}"}] @itemx @code{w} @var{var} | @code{$}@var{n} [@code{"@var{expression}"}] Add variable @var{var} (or field @code{$@var{n}}) to the watch list. @@ -26833,12 +27160,14 @@ then the debugger stops execution and prompts for a command. Otherwise, @cindex debugger commands, @code{undisplay} @cindex @code{undisplay} debugger command +@cindex stop automatic display, in debugger @item @code{undisplay} [@var{n}] Remove item number @var{n} (or all items, if no argument) from the automatic display list. @cindex debugger commands, @code{unwatch} @cindex @code{unwatch} debugger command +@cindex delete watchpoint @item @code{unwatch} [@var{n}] Remove item number @var{n} (or all items, if no argument) from the watch list. @@ -26859,6 +27188,8 @@ functions which called the one you are in. The commands for doing this are: @cindex debugger commands, @code{backtrace} @cindex @code{backtrace} debugger command @cindex @code{bt} debugger command (alias for @code{backtrace}) +@cindex call stack, display in debugger +@cindex traceback, display in debugger @item @code{backtrace} [@var{count}] @itemx @code{bt} [@var{count}] Print a backtrace of all function calls (stack frames), or innermost @var{count} @@ -26912,25 +27243,32 @@ The value for @var{what} should be one of the following: @c nested table @table @code @item args +@cindex show function arguments, in debugger Arguments of the selected frame. @item break +@cindex show breakpoints List all currently set breakpoints. @item display +@cindex automatic displays, in debugger List all items in the automatic display list. @item frame +@cindex describe call stack frame, in debugger Description of the selected stack frame. @item functions +@cindex list function definitions, in debugger List all function definitions including source file names and line numbers. @item locals +@cindex show local variables, in debugger Local variables of the selected frame. @item source +@cindex show name of current source file, in debugger The name of the current source file. Each time the program stops, the current source file is the file containing the current instruction. When the debugger first starts, the current source file is the first file @@ -26939,12 +27277,15 @@ included via the @option{-f} option. The be used at any time to change the current source. @item sources +@cindex show all source files, in debugger List all program sources. @item variables +@cindex list all global variables, in debugger List all global variables. @item watch +@cindex show watchpoints List all items in the watch list. @end table @end table @@ -26958,6 +27299,8 @@ from a file. The commands are: @cindex debugger commands, @code{option} @cindex @code{option} debugger command @cindex @code{o} debugger command (alias for @code{option}) +@cindex display debugger options +@cindex debugger options @item @code{option} [@var{name}[@code{=}@var{value}]] @itemx @code{o} [@var{name}[@code{=}@var{value}]] Without an argument, display the available debugger options @@ -26969,30 +27312,37 @@ The available options are: @c nested table @table @code @item history_size +@cindex debugger history size The maximum number of lines to keep in the history file @file{./.gawk_history}. The default is 100. @item listsize +@cindex debugger default list amount The number of lines that @code{list} prints. The default is 15. @item outfile +@cindex redirect @command{gawk} output, in debugger Send @command{gawk} output to a file; debugger output still goes to standard output. An empty string (@code{""}) resets output to standard output. @item prompt +@cindex debugger prompt The debugger prompt. The default is @samp{@w{gawk> }}. @item save_history @r{[}on @r{|} off@r{]} +@cindex debugger history file Save command history to file @file{./.gawk_history}. The default is @code{on}. @item save_options @r{[}on @r{|} off@r{]} +@cindex save debugger options Save current options to file @file{./.gawkrc} upon exit. The default is @code{on}. Options are read back in to the next session upon startup. @item trace @r{[}on @r{|} off@r{]} +@cindex instruction tracing, in debugger Turn instruction tracing on or off. The default is @code{off}. @end table @@ -27001,6 +27351,7 @@ Save the commands from the current session to the given file name, so that they can be replayed using the @command{source} command. @item @code{source} @var{filename} +@cindex debugger, read commands from a file Run command(s) from a file; an error in any command does not terminate execution of subsequent commands. Comments (lines starting with @samp{#}) are allowed in a command file. @@ -27099,8 +27450,8 @@ about the command @var{command}. @cindex debugger commands, @code{list} @cindex @code{list} debugger command @cindex @code{l} debugger command (alias for @code{list}) -@item @code{list} [@code{-} | @code{+} | @var{n} | @var{filename@code{:}n} | @var{n}--@var{m} | @var{function}] -@itemx @code{l} [@code{-} | @code{+} | @var{n} | @var{filename@code{:}n} | @var{n}--@var{m} | @var{function}] +@item @code{list} [@code{-} | @code{+} | @var{n} | @var{filename}@code{:}@var{n} | @var{n}--@var{m} | @var{function}] +@itemx @code{l} [@code{-} | @code{+} | @var{n} | @var{filename}@code{:}@var{n} | @var{n}--@var{m} | @var{function}] Print the specified lines (default 15) from the current source file or the file named @var{filename}. The possible arguments to @code{list} are as follows: @@ -27120,7 +27471,7 @@ Print lines centered around line number @var{n}. @item @var{n}--@var{m} Print lines from @var{n} to @var{m}. -@item @var{filename@code{:}n} +@item @var{filename}@code{:}@var{n} Print lines centered around line number @var{n} in source file @var{filename}. This command may change the current source file. @@ -27133,6 +27484,7 @@ function @var{function}. This command may change the current source file. @cindex debugger commands, @code{quit} @cindex @code{quit} debugger command @cindex @code{q} debugger command (alias for @code{quit}) +@cindex exit the debugger @item @code{quit} @itemx @code{q} Exit the debugger. Debugging is great fun, but sometimes we all have @@ -27156,6 +27508,8 @@ fairly self-explanatory, and using @code{stepi} and @code{nexti} while @node Readline Support @section Readline Support +@cindex command completion, in debugger +@cindex history expansion, in debugger If @command{gawk} is compiled with the @code{readline} library, you can take advantage of that library's command completion and history expansion @@ -27243,9 +27597,7 @@ be added, and of course feel free to try to add them yourself! @cindex arbitrary precision @cindex multiple precision @cindex infinite precision -@cindex floating-point numbers, arbitrary precision -@cindex MPFR -@cindex GMP +@cindex floating-point, numbers@comma{} arbitrary precision @cindex Knuth, Donald @quotation @@ -27589,23 +27941,38 @@ then the answer is @math{2^{53}}. @end iftex @ifnottex +@ifnotdocbook 2^53. +@end ifnotdocbook @end ifnottex +@docbook +2<superscript>53</superscript>. @c +@end docbook The next representable number is the even number @iftex @math{2^{53} + 2}, @end iftex @ifnottex +@ifnotdocbook 2^53 + 2, +@end ifnotdocbook @end ifnottex +@docbook +2<superscript>53</superscript> + 2, @c +@end docbook meaning it is unlikely that you will be able to make @command{gawk} print @iftex @math{2^{53} + 1} @end iftex @ifnottex +@ifnotdocbook 2^53 + 1 +@end ifnotdocbook @end ifnottex +@docbook +2<superscript>53</superscript> + 1 @c +@end docbook in integer format. The range of integers exactly representable by a 64-bit double is @@ -27613,8 +27980,13 @@ is @math{[-2^{53}, 2^{53}]}. @end iftex @ifnottex +@ifnotdocbook [@minus{}2^53, 2^53]. +@end ifnotdocbook @end ifnottex +@docbook +[−2<superscript>53</superscript>, 2<superscript>53</superscript>]. @c +@end docbook If you ever see an integer outside this range in @command{awk} using 64-bit doubles, you have reason to be very suspicious about the accuracy of the output. Here is a simple program with erroneous output: @@ -27838,8 +28210,13 @@ number is then @math{s @cdot 2^e}. @end iftex @ifnottex +@ifnotdocbook @var{s * 2^e}. +@end ifnotdocbook @end ifnottex +@docbook +<emphasis>s ⋅ 2<superscript>e</superscript></emphasis>. @c +@end docbook The first bit of a non-zero binary significand is always one, so the significand in an IEEE-754 format only includes the fractional part, leaving the leading one implicit. @@ -28009,6 +28386,8 @@ when you change the rounding mode. @node Gawk and MPFR @section @command{gawk} + MPFR = Powerful Arithmetic +@cindex MPFR +@cindex GMP The rest of this @value{CHAPTER} describes how to use the arbitrary precision (also known as @dfn{multiple precision} or @dfn{infinite precision}) numeric @@ -28021,12 +28400,17 @@ The easiest way to find out is to look at the output of the following command: @example -$ @kbd{gawk --version} -@print{} GNU Awk 4.1.0, API: 1.0 (GNU MPFR 3.1.0-p3, GNU MP 5.0.2) -@print{} Copyright (C) 1989, 1991-2013 Free Software Foundation. +$ @kbd{./gawk --version} +@print{} GNU Awk 4.1.1, API: 1.1 (GNU MPFR 3.1.0-p3, GNU MP 5.0.2) +@print{} Copyright (C) 1989, 1991-2014 Free Software Foundation. @dots{} @end example +@noindent +(You may see different version numbers than what's shown here. That's OK; +what's important is to see that GNU MPFR and GNU MP are listed in +the output.) + @command{gawk} uses the @uref{http://www.mpfr.org, GNU MPFR} and @@ -28080,8 +28464,13 @@ numbers are not implemented.} (@math{emax = 2^{30} - 1, emin = -emax}) @end iftex @ifnottex +@ifnotdocbook (@var{emax} = 2^30 @minus{} 1, @var{emin} = @minus{}@var{emax}) +@end ifnotdocbook @end ifnottex +@docbook +(<emphasis>emax</emphasis> = 2<superscript>30</superscript> − 1, <emphasis>emin</emphasis> = −<emphasis>emax</emphasis>) @c +@end docbook for all floating-point contexts. There is no explicit mechanism to adjust the exponent range. MPFR does not implement subnormal numbers by default, @@ -28113,6 +28502,7 @@ your program. @node Setting Precision @subsection Setting the Working Precision @cindex @code{PREC} variable +@cindex setting working precision @command{gawk} uses a global working precision; it does not keep track of the precision or accuracy of individual numbers. Performing an arithmetic @@ -28152,8 +28542,15 @@ formula: @math{prec = 3.322 @cdot dps} @end iftex @ifnottex +@ifnotdocbook @var{prec} = 3.322 * @var{dps} +@end ifnotdocbook @end ifnottex +@docbook +<para> +<emphasis>prec</emphasis> = 3.322 ⋅ <emphasis>dps</emphasis> @c +</para> +@end docbook @noindent Here, @var{prec} denotes the binary precision @@ -28188,6 +28585,7 @@ issues that occur because numbers are stored internally in binary. @node Setting Rounding Mode @subsection Setting the Rounding Mode @cindex @code{ROUNDMODE} variable +@cindex setting rounding mode The @code{ROUNDMODE} variable provides program level control over the rounding mode. @@ -28255,6 +28653,7 @@ In the first case, the number is stored with the default precision of 53 bits. @node Changing Precision @subsection Changing the Precision of a Number +@cindex changing precision of a number @cindex Laurie, Dirk @quotation @@ -28372,7 +28771,8 @@ the problem at hand is often the correct approach in such situations. @node Arbitrary Precision Integers @section Arbitrary Precision Integer Arithmetic with @command{gawk} -@cindex integer, arbitrary precision +@cindex integers, arbitrary precision +@cindex arbitrary precision integers If one of the options @option{--bignum} or @option{-M} is specified, @command{gawk} performs all @@ -28386,8 +28786,13 @@ For example, the following computes @math{5^{4^{3^{2}}}}, @end iftex @ifnottex +@ifnotdocbook 5^4^3^2, +@end ifnotdocbook @end ifnottex +@docbook +5<superscript>4<superscript>3<superscript>2</superscript></superscript></superscript>, @c +@end docbook the result of which is beyond the limits of ordinary @command{gawk} numbers: @@ -28409,9 +28814,16 @@ floating-point values instead, the precision needed for correct output would be @math{3.322 @cdot 183231}, @end iftex @ifnottex +@ifnotdocbook @samp{prec = 3.322 * dps}), would be 3.322 x 183231, +@end ifnotdocbook @end ifnottex +@docbook +<emphasis>prec</emphasis> = 3.322 ⋅ <emphasis>dps</emphasis>), +would be +<emphasis>prec</emphasis> = 3.322 ⋅ 183231, @c +@end docbook or 608693. The result from an arithmetic operation with an integer and a floating-point value @@ -28460,7 +28872,7 @@ to begin with: gawk -M 'BEGIN @{ n = 13.0; print n % 2.0 @}' @end example -Note that for the particular example above, there is likely best +Note that for the particular example above, it is likely best to just use the following: @example @@ -28469,6 +28881,7 @@ gawk -M 'BEGIN @{ n = 13; print n % 2 @}' @node Dynamic Extensions @chapter Writing Extensions for @command{gawk} +@cindex dynamically loaded extensions It is possible to add new functions written in C or C++ to @command{gawk} using dynamically loaded libraries. This facility is available on systems @@ -28503,6 +28916,7 @@ When @option{--sandbox} is specified, extensions are disabled @node Extension Intro @section Introduction +@cindex plug-in An @dfn{extension} (sometimes called a @dfn{plug-in}) is a piece of external compiled code that @command{gawk} can load at runtime to provide additional functionality, over and above the built-in capabilities @@ -28548,8 +28962,14 @@ Communication between @command{gawk} and an extension is two-way. First, when an extension is loaded, it is passed a pointer to a @code{struct} whose fields are function pointers. +@ifnotdocbook This is shown in @ref{load-extension}. +@end ifnotdocbook +@ifdocbook +This is shown in @inlineraw{docbook, <xref linkend="load-extension"/>}. +@end ifdocbook +@ifnotdocbook @float Figure,load-extension @caption{Loading The Extension} @c FIXME: One day, it should not be necessary to have two cases, @@ -28562,13 +28982,27 @@ This is shown in @ref{load-extension}. @center @image{api-figure1, , , Loading the extension} @end ifnotinfo @end float +@end ifnotdocbook + +@docbook +<figure id="load-extension"> +<title>Loading the extension</title> +<graphic fileref="api-figure1.eps"/> +</figure> +@end docbook The extension can call functions inside @command{gawk} through these function pointers, at runtime, without needing (link-time) access to @command{gawk}'s symbols. One of these function pointers is to a function for ``registering'' new built-in functions. +@ifnotdocbook This is shown in @ref{load-new-function}. +@end ifnotdocbook +@ifdocbook +This is shown in @inlineraw{docbook, <xref linkend="load-new-function"/>}. +@end ifdocbook +@ifnotdocbook @float Figure,load-new-function @caption{Loading The New Function} @ifinfo @@ -28578,14 +29012,28 @@ This is shown in @ref{load-new-function}. @center @image{api-figure2, , , Loading the new function} @end ifnotinfo @end float +@end ifnotdocbook + +@docbook +<figure id="load-new-function"> +<title>Loading the new function</title> +<graphic fileref="api-figure2.eps"/> +</figure> +@end docbook In the other direction, the extension registers its new functions with @command{gawk} by passing function pointers to the functions that provide the new feature (@code{do_chdir()}, for example). @command{gawk} associates the function pointer with a name and can then call it, using a defined calling convention. +@ifnotdocbook This is shown in @ref{call-new-function}. +@end ifnotdocbook +@ifdocbook +This is shown in @inlineraw{docbook, <xref linkend="call-new-function"/>}. +@end ifdocbook +@ifnotdocbook @float Figure,call-new-function @caption{Calling The New Function} @ifinfo @@ -28595,6 +29043,14 @@ This is shown in @ref{call-new-function}. @center @image{api-figure3, , , Calling the new function} @end ifnotinfo @end float +@end ifnotdocbook + +@docbook +<figure id="call-new-function"> +<title>Calling The New Function</title> +<graphic fileref="api-figure3.eps"/> +</figure> +@end docbook The @code{do_@var{xxx}()} function, in turn, then uses the function pointers in the API @code{struct} to do its work, such as updating @@ -28631,6 +29087,7 @@ happen, but we all know how @emph{that} goes.) @node Extension API Description @section API Description +@cindex extension API This (rather large) @value{SECTION} describes the API in detail. @@ -28638,6 +29095,7 @@ This (rather large) @value{SECTION} describes the API in detail. * Extension API Functions Introduction:: Introduction to the API functions. * General Data Types:: The data types. * Requesting Values:: How to get a value. +* Memory Allocation Functions:: Functions for allocating memory. * Constructor Functions:: Functions for creating values. * Registration Functions:: Functions to register things with @command{gawk}. @@ -28693,6 +29151,9 @@ Symbol table access: retrieving a global variable, creating one, or changing one. @item +Allocating, reallocating, and releasing memory. + +@item Creating and releasing cached values; this provides an efficient way to use values for multiple variables and can be a big performance win. @@ -28731,10 +29192,8 @@ corresponding standard header file @emph{before} including @file{gawkapi.h}: @item @code{EOF} @tab @code{<stdio.h>} @item @code{FILE} @tab @code{<stdio.h>} @item @code{NULL} @tab @code{<stddef.h>} -@item @code{malloc()} @tab @code{<stdlib.h>} @item @code{memcpy()} @tab @code{<string.h>} @item @code{memset()} @tab @code{<string.h>} -@item @code{realloc()} @tab @code{<stdlib.h>} @item @code{size_t} @tab @code{<sys/types.h>} @item @code{struct stat} @tab @code{<sys/stat.h>} @end multitable @@ -28764,8 +29223,9 @@ does not support this keyword, you should either place All pointers filled in by @command{gawk} are to memory managed by @command{gawk} and should be treated by the extension as read-only. Memory for @emph{all} strings passed into @command{gawk} -from the extension @emph{must} come from @code{malloc()} and is managed -by @command{gawk} from then on. +from the extension @emph{must} come from calling the API-provided function +pointers @code{api_malloc()}, @code{api_calloc()} or @code{api_realloc()}, +and is managed by @command{gawk} from then on. @item The API defines several simple @code{struct}s that map values as seen @@ -28805,6 +29265,8 @@ the macros as if they were functions. @node General Data Types @subsection General Purpose Data Types +@cindex Robbins, Arnold +@cindex Ramey, Chet @quotation @i{I have a true love/hate relationship with unions.} @author Arnold Robbins @@ -28845,7 +29307,8 @@ A simple boolean type. This represents a mutable string. @command{gawk} owns the memory pointed to if it supplied the value. Otherwise, it takes ownership of the memory pointed to. -@strong{Such memory must come from @code{malloc()}!} +@strong{Such memory must come from calling the API-provided function +pointers @code{api_malloc()}, @code{api_calloc()}, or @code{api_realloc()}!} As mentioned earlier, strings are maintained using the current multibyte encoding. @@ -28961,7 +29424,94 @@ print an error message, or reissue the request for the actual value type, as appropriate. This behavior is summarized in @ref{table-value-types-returned}. +@c FIXME: Try to do this with spans... +@ifdocbook +@anchor{table-value-types-returned} +@end ifdocbook +@docbook +<informaltable> +<tgroup cols="2"> + <colspec colwidth="50*"/><colspec colwidth="50*"/> + <thead> + <row><entry></entry><entry><para>Type of Actual Value:</para></entry></row> + </thead> + <tbody> + <row><entry></entry><entry></entry></row> + </tbody> +</tgroup> +<tgroup cols="6"> + <colspec colwidth="16.6*"/> + <colspec colwidth="16.6*"/> + <colspec colwidth="19.8*"/> + <colspec colwidth="15*"/> + <colspec colwidth="15*"/> + <colspec colwidth="16.6*"/> + <thead> + <row> + <entry></entry> + <entry></entry> + <entry><para>String</para></entry> + <entry><para>Number</para></entry> + <entry><para>Array</para></entry> + <entry><para>Undefined</para></entry> + </row> + </thead> + <tbody> + <row> + <entry></entry> + <entry><para><emphasis role="bold">String</emphasis></para></entry> + <entry><para>String</para></entry> + <entry><para>String</para></entry> + <entry><para>false</para></entry> + <entry><para>false</para></entry> + </row> + <row> + <entry></entry> + <entry><para><emphasis role="bold">Number</emphasis></para></entry> + <entry><para>Number if can be converted, else false</para></entry> + <entry><para>Number</para></entry> + <entry><para>false</para></entry> + <entry><para>false</para></entry> + </row> + <row> + <entry><para><emphasis role="bold">Type</emphasis></para></entry> + <entry><para><emphasis role="bold">Array</emphasis></para></entry> + <entry><para>false</para></entry> + <entry><para>false</para></entry> + <entry><para>Array</para></entry> + <entry><para>false</para></entry> + </row> + <row> + <entry><para><emphasis role="bold">Requested:</emphasis></para></entry> + <entry><para><emphasis role="bold">Scalar</emphasis></para></entry> + <entry><para>Scalar</para></entry> + <entry><para>Scalar</para></entry> + <entry><para>false</para></entry> + <entry><para>false</para></entry> + </row> + <row> + <entry></entry> + <entry><para><emphasis role="bold">Undefined</emphasis></para></entry> + <entry><para>String</para></entry> + <entry><para>Number</para></entry> + <entry><para>Array</para></entry> + <entry><para>Undefined</para></entry> + </row> + <row> + <entry></entry> + <entry><para><emphasis role="bold">Value Cookie</emphasis></para></entry> + <entry><para>false</para></entry> + <entry><para>false</para></entry> + <entry><para>false</para> + </entry><entry><para>false</para></entry> + </row> + </tbody> +</tgroup> +</informaltable> +@end docbook + @ifnotplaintext +@ifnotdocbook @float Table,table-value-types-returned @caption{Value Types Returned} @multitable @columnfractions .50 .50 @@ -28977,6 +29527,7 @@ value type, as appropriate. This behavior is summarized in @item @tab @b{Value Cookie} @tab false @tab false @tab false @tab false @end multitable @end float +@end ifnotdocbook @end ifnotplaintext @ifplaintext @float Table,table-value-types-returned @@ -29007,45 +29558,46 @@ value type, as appropriate. This behavior is summarized in @end float @end ifplaintext -@node Constructor Functions -@subsection Constructor Functions and Convenience Macros +@node Memory Allocation Functions +@subsection Memory Allocation Functions and Convenience Macros +@cindex allocating memory for extensions +@cindex extensions, allocating memory -The API provides a number of @dfn{constructor} functions for creating -string and numeric values, as well as a number of convenience macros. -This @value{SUBSECTION} presents them all as function prototypes, in -the way that extension code would use them. +The API provides a number of @dfn{memory allocation} functions for +allocating memory that can be passed to @command{gawk}, as well as a number of +convenience macros. @table @code -@item static inline awk_value_t * -@itemx make_const_string(const char *string, size_t length, awk_value_t *result) -This function creates a string value in the @code{awk_value_t} variable -pointed to by @code{result}. It expects @code{string} to be a C string constant -(or other string data), and automatically creates a @emph{copy} of the data -for storage in @code{result}. It returns @code{result}. +@item void *gawk_malloc(size_t size); +Call @command{gawk}-provided @code{api_malloc()} to allocate storage that may +be passed to @command{gawk}. -@item static inline awk_value_t * -@itemx make_malloced_string(const char *string, size_t length, awk_value_t *result) -This function creates a string value in the @code{awk_value_t} variable -pointed to by @code{result}. It expects @code{string} to be a @samp{char *} -value pointing to data previously obtained from @code{malloc()}. The idea here -is that the data is passed directly to @command{gawk}, which assumes -responsibility for it. It returns @code{result}. +@item void *gawk_calloc(size_t nmemb, size_t size); +Call @command{gawk}-provided @code{api_calloc()} to allocate storage that may +be passed to @command{gawk}. -@item static inline awk_value_t * -@itemx make_null_string(awk_value_t *result) -This specialized function creates a null string (the ``undefined'' value) -in the @code{awk_value_t} variable pointed to by @code{result}. -It returns @code{result}. +@item void *gawk_realloc(void *ptr, size_t size); +Call @command{gawk}-provided @code{api_realloc()} to allocate storage that may +be passed to @command{gawk}. -@item static inline awk_value_t * -@itemx make_number(double num, awk_value_t *result) -This function simply creates a numeric value in the @code{awk_value_t} variable -pointed to by @code{result}. +@item void gawk_free(void *ptr); +Call @command{gawk}-provided @code{api_free()} to release storage that was +allocated with @code{gawk_malloc()}, @code{gawk_calloc()} or @code{gawk_realloc()}. @end table -Two convenience macros may be used for allocating storage from @code{malloc()} -and @code{realloc()}. If the allocation fails, they cause @command{gawk} to -exit with a fatal error message. They should be used as if they were +The API has to provide these functions because it is possible +for an extension to be compiled and linked against a different +version of the C library than was used for the @command{gawk} +executable.@footnote{This is more common on MS-Windows systems, but +can happen on Unix-like systems as well.} If @command{gawk} were +to use its version of @code{free()} when the memory came from an +unrelated version of @code{malloc()}, unexpected behavior would +likely result. + +Two convenience macros may be used for allocating storage +from the API-provided function pointers @code{api_malloc()} and +@code{api_realloc()}. If the allocation fails, they cause @command{gawk} +to exit with a fatal error message. They should be used as if they were procedure calls that do not return a value. @table @code @@ -29057,7 +29609,7 @@ The arguments to this macro are as follows: The pointer variable to point at the allocated storage. @item type -The type of the pointer variable, used to create a cast for the call to @code{malloc()}. +The type of the pointer variable, used to create a cast for the call to @code{api_malloc()}. @item size The total number of bytes to be allocated. @@ -29081,13 +29633,51 @@ make_malloced_string(message, strlen(message), & result); @end example @item #define erealloc(pointer, type, size, message) @dots{} -This is like @code{emalloc()}, but it calls @code{realloc()}, -instead of @code{malloc()}. +This is like @code{emalloc()}, but it calls @code{api_realloc()}, +instead of @code{api_malloc()}. The arguments are the same as for the @code{emalloc()} macro. @end table +@node Constructor Functions +@subsection Constructor Functions + +The API provides a number of @dfn{constructor} functions for creating +string and numeric values, as well as a number of convenience macros. +This @value{SUBSECTION} presents them all as function prototypes, in +the way that extension code would use them. + +@table @code +@item static inline awk_value_t * +@itemx make_const_string(const char *string, size_t length, awk_value_t *result) +This function creates a string value in the @code{awk_value_t} variable +pointed to by @code{result}. It expects @code{string} to be a C string constant +(or other string data), and automatically creates a @emph{copy} of the data +for storage in @code{result}. It returns @code{result}. + +@item static inline awk_value_t * +@itemx make_malloced_string(const char *string, size_t length, awk_value_t *result) +This function creates a string value in the @code{awk_value_t} variable +pointed to by @code{result}. It expects @code{string} to be a @samp{char *} +value pointing to data previously obtained from the api-provided functions @code{api_malloc()}, @code{api_calloc()} or @code{api_realloc()}. The idea here +is that the data is passed directly to @command{gawk}, which assumes +responsibility for it. It returns @code{result}. + +@item static inline awk_value_t * +@itemx make_null_string(awk_value_t *result) +This specialized function creates a null string (the ``undefined'' value) +in the @code{awk_value_t} variable pointed to by @code{result}. +It returns @code{result}. + +@item static inline awk_value_t * +@itemx make_number(double num, awk_value_t *result) +This function simply creates a numeric value in the @code{awk_value_t} variable +pointed to by @code{result}. +@end table + @node Registration Functions @subsection Registration Functions +@cindex register extension +@cindex extension registration This @value{SECTION} describes the API functions for registering parts of your extension with @command{gawk}. @@ -29132,8 +29722,8 @@ Letter case in function names is significant. This is a pointer to the C function that provides the desired functionality. The function must fill in the result with either a number -or a string. @command{awk} takes ownership of any string memory. -As mentioned earlier, string memory @strong{must} come from @code{malloc()}. +or a string. @command{gawk} takes ownership of any string memory. +As mentioned earlier, string memory @strong{must} come from the api-provided functions @code{api_malloc()}, @code{api_calloc()} or @code{api_realloc()}. The @code{num_actual_args} argument tells the C function how many actual parameters were passed from the calling @command{awk} code. @@ -29209,6 +29799,7 @@ is invoked with the @option{--version} option. @node Input Parsers @subsubsection Customized Input Parsers +@cindex customized input parser By default, @command{gawk} reads text files as its input. It uses the value of @code{RS} to find the end of the record, and then uses @code{FS} @@ -29456,7 +30047,9 @@ Register the input parser pointed to by @code{input_parser} with @node Output Wrappers @subsubsection Customized Output Wrappers +@cindex customized output wrapper +@cindex output wrapper An @dfn{output wrapper} is the mirror image of an input parser. It allows an extension to take over the output to a file opened with the @samp{>} or @samp{>>} I/O redirection operators (@pxref{Redirection}). @@ -29570,6 +30163,7 @@ Register the output wrapper pointed to by @code{output_wrapper} with @node Two-way processors @subsubsection Customized Two-way Processors +@cindex customized two-way processor A @dfn{two-way processor} combines an input parser and an output wrapper for two-way I/O with the @samp{|&} operator (@pxref{Redirection}). It makes identical @@ -29627,6 +30221,8 @@ Register the two-way processor pointed to by @code{two_way_processor} with @node Printing Messages @subsection Printing Messages +@cindex printing messages from extensions +@cindex messages from extensions You can print different kinds of warning messages from your extension, as described below. Note that for these functions, @@ -29700,6 +30296,7 @@ for more information on creating arrays. @node Symbol Table Access @subsection Symbol Table Access +@cindex accessing global variables from extensions Two sets of routines provide access to global variables, and one set allows you to create and release cached values. @@ -29745,6 +30342,13 @@ An extension can look up the value of @command{gawk}'s special variables. However, with the exception of the @code{PROCINFO} array, an extension cannot change any of those variables. +@quotation NOTE +It is possible for the lookup of @code{PROCINFO} to fail. This happens if +the @command{awk} program being run does not reference @code{PROCINFO}; +in this case @command{gawk} doesn't bother to create the array and +populate it. +@end quotation + @node Symbol table by cookie @subsubsection Variable Access and Update by Cookie @@ -29871,7 +30475,7 @@ assign those values to variables using @code{sym_update()} or @code{sym_update_scalar()}, as you like. However, you can understand the point of cached values if you remember that -@emph{every} string value's storage @emph{must} come from @code{malloc()}. +@emph{every} string value's storage @emph{must} come from @code{api_malloc()}, @code{api_calloc()} or @code{api_realloc()}. If you have 20 variables, all of which have the same string value, you must create 20 identical copies of the string.@footnote{Numeric values are clearly less problematic, requiring only a C @code{double} to store.} @@ -29957,6 +30561,7 @@ you should release any cached values that you created, using @node Array Manipulation @subsection Array Manipulation +@cindex array manipulation in extensions The primary data structure@footnote{Okay, the only data structure.} in @command{awk} is the associative array (@pxref{Arrays}). @@ -30068,7 +30673,7 @@ requires that you understand how such values are converted to strings (@pxref{Conversion}); thus using integral values is safest. As with @emph{all} strings passed into @code{gawk} from an extension, -the string value of @code{index} must come from @code{malloc()}, and +the string value of @code{index} must come from the API-provided functions @code{api_malloc()}, @code{api_calloc()} or @code{api_realloc()} and @command{gawk} releases the storage. @item awk_bool_t set_array_element(awk_array_t a_cookie, @@ -30536,6 +31141,8 @@ information about how @command{gawk} was invoked. @node Extension Versioning @subsubsection API Version Constants and Variables +@cindex API version +@cindex extension API version The API provides both a ``major'' and a ``minor'' version number. The API versions are available at compile time as constants: @@ -30589,6 +31196,8 @@ provided in @file{gawkapi.h} (discussed later, in @node Extension API Informational Variables @subsubsection Informational Variables +@cindex API informational variables +@cindex extension API informational variables The API provides access to several variables that describe whether the corresponding command-line options were enabled when @@ -30734,6 +31343,8 @@ the version string with @command{gawk}. @node Finding Extensions @section How @command{gawk} Finds Extensions +@cindex extension search path +@cindex finding extensions Compiled extensions have to be installed in a directory where @command{gawk} can find them. If @command{gawk} is configured and @@ -30744,6 +31355,7 @@ path with a list of directories to search for compiled extensions. @node Extension Example @section Example: Some File Functions +@cindex extension example @quotation @i{No matter where you go, there you are.} @@ -31202,7 +31814,7 @@ do_stat(int nargs, awk_value_t *result) awk_array_t array; int ret; struct stat sbuf; - /* default is stat() */ + /* default is lstat() */ int (*statfunc)(const char *path, struct stat *sbuf) = lstat; assert(result != NULL); @@ -31388,6 +32000,7 @@ $ @kbd{AWKLIBPATH=$PWD gawk -f testff.awk} @node Extension Samples @section The Sample Extensions In The @command{gawk} Distribution +@cindex extensions distributed with @command{gawk} This @value{SECTION} provides brief overviews of the sample extensions that come in the @command{gawk} distribution. Some of them are intended @@ -31430,7 +32043,7 @@ upon success or less than zero upon error. In the latter case it updates @code{ERRNO}. @cindex @code{stat()} extension function -@item result = stat("/some/path", statdata [, follow]) +@item result = stat("/some/path", statdata @r{[}, follow@r{]}) The @code{stat()} function provides a hook into the @code{stat()} system call. It returns zero upon success or less than zero upon error. @@ -31640,19 +32253,23 @@ See @file{test/fts.awk} in the @command{gawk} distribution for an example. @node Extension Sample Fnmatch @subsection Interface To @code{fnmatch()} -@cindex @code{fnmatch()} extension function This extension provides an interface to the C library @code{fnmatch()} function. The usage is: -@example -@@load "fnmatch" +@table @code +@item @@load "fnmatch" +This is how you load the extension. -result = fnmatch(pattern, string, flags) -@end example +@cindex @code{fnmatch()} extension function +@item result = fnmatch(pattern, string, flags) +The return value is zero on success, @code{FNM_NOMATCH} +if the string did not match the pattern, or +a different non-zero value if an error occurred. +@end table -The @code{fnmatch} extension adds a single function named -@code{fnmatch()}, one constant (@code{FNM_NOMATCH}), and an array of -flag values named @code{FNM}. +Besides the @code{fnmatch()} function, the @code{fnmatch} extension +adds one constant (@code{FNM_NOMATCH}), and an array of flag values +named @code{FNM}. The arguments to @code{fnmatch()} are: @@ -31668,10 +32285,6 @@ Either zero, or the bitwise OR of one or more of the flags in the @code{FNM} array. @end table -The return value is zero on success, @code{FNM_NOMATCH} -if the string did not match the pattern, or -a different non-zero value if an error occurred. - The flags are follows: @multitable @columnfractions .25 .75 @@ -31715,15 +32328,15 @@ This is how you load the extension. @cindex @code{fork()} extension function @item pid = fork() -This function creates a new process. The return value is the zero in the -child and the process-id number of the child in the parent, or @minus{}1 +This function creates a new process. The return value is zero in the +child and the process-ID number of the child in the parent, or @minus{}1 upon error. In the latter case, @code{ERRNO} indicates the problem. In the child, @code{PROCINFO["pid"]} and @code{PROCINFO["ppid"]} are updated to reflect the correct values. @cindex @code{waitpid()} extension function @item ret = waitpid(pid) -This function takes a numeric argument, which is the process-id to +This function takes a numeric argument, which is the process-ID to wait for. The return value is that of the @code{waitpid()} system call. @@ -31979,7 +32592,7 @@ ret = reada("arraydump.bin", array) @subsection Reading An Entire File The @code{readfile} extension adds a single function -named @code{readfile()}: +named @code{readfile()}, and an input parser: @table @code @item @@load "readfile" @@ -31990,6 +32603,12 @@ This is how you load the extension. The argument is the name of the file to read. The return value is a string containing the entire contents of the requested file. Upon error, the function returns the empty string and sets @code{ERRNO}. + +@item BEGIN @{ PROCINFO["readfile"] = 1 @} +In addition, the extension adds an input parser that is activated if +@code{PROCINFO["readfile"]} exists. +When activated, each input file is returned in its entirety as @code{$0}. +@code{RT} is set to the null string. @end table Here is an example: @@ -32048,6 +32667,8 @@ tries to use @code{nanosleep()} or @code{select()} to implement the delay. @node gawkextlib @section The @code{gawkextlib} Project +@cindex @code{gawkextlib} +@cindex extensions, where to find @cindex @code{gawkextlib} project The @uref{http://sourceforge.net/projects/gawkextlib/, @code{gawkextlib}} @@ -32081,6 +32702,7 @@ The @code{time} extension described earlier (@pxref{Extension Sample Time}) was originally from this project but has been moved in to the main @command{gawk} distribution. +@cindex @command{git} utility You can check out the code for the @code{gawkextlib} project using the @uref{http://git-scm.com, GIT} distributed source code control system. The command is as follows: @@ -33347,7 +33969,7 @@ The @option{-i} and @option{--include} options load @command{awk} library files. @item -The @option{-l} and @option{--load} options for load compiled dynamic extensions. +The @option{-l} and @option{--load} options load compiled dynamic extensions. @item The @option{-M} and @option{--bignum} options enable MPFR. @@ -33368,7 +33990,7 @@ Support for high precision arithmetic with MPFR. @item The @code{and()}, @code{or()} and @code{xor()} functions -allow any number of arguments, +changed to allow any number of arguments, with a minimum of two (@pxref{Bitwise Functions}). @@ -33393,18 +34015,18 @@ the three most widely-used freely available versions of @command{awk} @multitable {@file{/dev/stderr} special file} {BWK Awk} {Mawk} {GNU Awk} @headitem Feature @tab BWK Awk @tab Mawk @tab GNU Awk @item @samp{\x} Escape sequence @tab X @tab X @tab X -@item @code{RS} as regexp @tab @tab X @tab X @item @code{FS} as null string @tab X @tab X @tab X @item @file{/dev/stdin} special file @tab X @tab X @tab X @item @file{/dev/stdout} special file @tab X @tab X @tab X @item @file{/dev/stderr} special file @tab X @tab X @tab X -@item @code{**} and @code{**=} operators @tab X @tab @tab X -@item @code{fflush()} function @tab X @tab X @tab X -@item @code{func} keyword @tab X @tab @tab X -@item @code{nextfile} statement @tab X @tab X @tab X @item @code{delete} without subscript @tab X @tab X @tab X +@item @code{fflush()} function @tab X @tab X @tab X @item @code{length()} of an array @tab X @tab X @tab X +@item @code{nextfile} statement @tab X @tab X @tab X +@item @code{**} and @code{**=} operators @tab X @tab @tab X +@item @code{func} keyword @tab X @tab @tab X @item @code{BINMODE} variable @tab @tab X @tab X +@item @code{RS} as regexp @tab @tab X @tab X @item Time related functions @tab @tab X @tab X @end multitable @@ -33435,7 +34057,7 @@ as working in this fashion, and in particular, would teach that the that @samp{[A-Z]} was the ``correct'' way to match uppercase letters. And indeed, this was true.@footnote{And Life was good.} -The 1993 POSIX standard introduced the idea of locales (@pxref{Locales}). +The 1992 POSIX standard introduced the idea of locales (@pxref{Locales}). Since many locales include other letters besides the plain twenty-six letters of the American English alphabet, the POSIX standard added character classes (@pxref{Bracket Expressions}) as a way to match @@ -33474,6 +34096,7 @@ This output is unexpected, since the @samp{bc} at the end of This result is due to the locale setting (and thus you may not see it on your system). +@cindex Unicode Similar considerations apply to other ranges. For example, @samp{["-/]} is perfectly valid in ASCII, but is not valid in many Unicode locales, such as @samp{en_US.UTF-8}. @@ -33487,16 +34110,17 @@ vendors started implementing non-ASCII locales, @emph{and making them the default}. Perhaps the most frequently asked question became something like ``why does @samp{[A-Z]} match lowercase letters?!?'' +@cindex Berry, Karl This situation existed for close to 10 years, if not more, and the @command{gawk} maintainer grew weary of trying to explain that @command{gawk} was being nicely standards-compliant, and that the issue was in the user's locale. During the development of version 4.0, he modified @command{gawk} to always treat ranges in the original, pre-POSIX fashion, unless @option{--posix} was used (@pxref{Options}).@footnote{And -thus was born the Campain for Rational Range Interpretation (or RRI). A number -of GNU tools, such as @command{grep} and @command{sed}, have either -implemented this change, or will soon. Thanks to Karl Berry for coining the phrase -``Rational Range Interpretation.''} +thus was born the Campaign for Rational Range Interpretation (or +RRI). A number of GNU tools have either implemented this change, +or will soon. Thanks to Karl Berry for coining the phrase ``Rational +Range Interpretation.''} Fortunately, shortly before the final release of @command{gawk} 4.0, the maintainer learned that the 2008 standard had changed the @@ -33509,7 +34133,7 @@ and By using this lovely technical term, the standard gives license to implementors to implement ranges in whatever way they choose. The @command{gawk} maintainer chose to apply the pre-POSIX meaning in all -cases: the default regexp matching; with @option{--traditional}, and with +cases: the default regexp matching; with @option{--traditional} and with @option{--posix}; in all cases, @command{gawk} remains POSIX compliant. @node Contributors @@ -33709,6 +34333,11 @@ environments. Anders Wallin helped keep the VMS port going for several years. @item +@cindex Gordon, Assaf +Assaf Gordon contributed the code to implement the +@option{--sandbox} option. + +@item @cindex Haque, John John Haque made the following contributions: @@ -33752,6 +34381,11 @@ Arnold Robbins and Andrew Schorr, with notable contributions from the rest of the development team. @item +@cindex Colombo, Antonio +Antonio Giovanni Colombo rewrote a number of examples in the early +chapters that were severely dated, for which I am incredibly grateful. + +@item @cindex Robbins, Arnold Arnold Robbins has been working on @command{gawk} since 1988, at first @@ -34150,7 +34784,7 @@ please send in a bug report (@pxref{Bugs}). Of course, once you've built @command{gawk}, it is likely that you will wish to install it. To do so, you need to run the command @samp{make -check}, as a user with the appropriate permissions. How to do this +install}, as a user with the appropriate permissions. How to do this varies by system, but on many systems you can use the @command{sudo} command to do so. The command then becomes @samp{sudo make install}. It is likely that you will be asked for your password, and you will have @@ -34476,11 +35110,10 @@ multibyte functionality is not available. @c STARTOFRANGE pcgawon @cindex PC operating systems, @command{gawk} on -With the exception of the Cygwin environment, -the @samp{|&} operator and TCP/IP networking -(@pxref{TCP/IP Networking}) -are not supported for MS-DOS or MS-Windows. EMX (OS/2 only) does support -at least the @samp{|&} operator. +Under MS-DOS and MS-Windows, the Cygwin and MinGW environments support +both the @samp{|&} operator and TCP/IP networking +(@pxref{TCP/IP Networking}). +EMX (OS/2 only) supports at least the @samp{|&} operator. @cindex search paths @cindex search paths, for source files @@ -34610,7 +35243,7 @@ moved into the @code{BEGIN} rule. @command{gawk} can be built and used ``out of the box'' under MS-Windows if you are using the @uref{http://www.cygwin.com, Cygwin environment}. -This environment provides an excellent simulation of Unix, using the +This environment provides an excellent simulation of GNU/Linux, using the GNU tools, such as Bash, the GNU Compiler Collection (GCC), GNU Make, and other GNU programs. Compilation and installation for Cygwin is the same as for a Unix system: @@ -34626,13 +35259,6 @@ When compared to GNU/Linux on the same system, the @samp{configure} step on Cygwin takes considerably longer. However, it does finish, and then the @samp{make} proceeds as usual. -@quotation NOTE -The @samp{|&} operator and TCP/IP networking -(@pxref{TCP/IP Networking}) -are fully supported in the Cygwin environment. This is not true -for any other environment on MS-Windows. -@end quotation - @node MSYS @appendixsubsubsec Using @command{gawk} In The MSYS Environment @@ -34700,21 +35326,14 @@ can better handle @code{ODS-5} volumes with upper- and lowercase filenames. With @code{ODS-5} volumes and extended parsing enabled, the case of the target parameter may need to be exact. -Older versions of @command{gawk} could be built with VAX C or -GNU C on VAX/VMS, as well as with DEC C, but that is no longer -supported. DEC C (also briefly known as ``Compaq C'' and now known -as ``HP C,'' but referred to here as ``DEC C'') is required. Both -@code{vmsbuild.com} and @code{descrip.mms} contain some obsolete support -for the older compilers but are set up to use DEC C by default. - @command{gawk} has been tested under VAX/VMS 7.3 and Alpha/VMS 7.3-1 using Compaq C V6.4, and Alpha/VMS 7.3, Alpha/VMS 7.3-2, and IA64/VMS 8.3. The most recent builds used HP C V7.3 on Alpha VMS 8.3 and both Alpha and IA64 VMS 8.4 used HP C 7.3.@footnote{The IA64 architecture is also known as ``Itanium.''} -Work is currently being done for a procedure to build @command{gawk} and create -a PCSI kit for compatible with the GNV product. +The @file{[.vms]gawk_build_steps.txt} provides information on how to build +@command{gawk} into a PCSI kit that is compatible with the GNV product. @node VMS Dynamic Extensions @appendixsubsubsec Compiling @command{gawk} Dynamic Extensions on VMS @@ -34811,7 +35430,7 @@ add the @command{gawk} and @command{awk} to the system wide @samp{DCLTABLES}. The DCL syntax is documented in the @file{gawk.hlp} file. -Optionally, @file{gawk.hlp} entry can be loaded into a VMS help library: +Optionally, the @file{gawk.hlp} entry can be loaded into a VMS help library: @example $ @kbd{LIBRARY/HELP sys$help:helplib [.vms]gawk.hlp} @@ -35066,22 +35685,23 @@ file should be considered authoritative if it conflicts with this The people maintaining the non-Unix ports of @command{gawk} are as follows: -@multitable {MS-Windows with MINGW} {123456789012345678901234567890123456789001234567890} +@c put the index entries outside the table, for docbook @cindex Deifik, Scott +@cindex Zaretskii, Eli +@cindex Buening, Andreas +@cindex Rankin, Pat +@cindex Malmberg, John +@cindex Pitts, Dave +@multitable {MS-Windows with MINGW} {123456789012345678901234567890123456789001234567890} @item MS-DOS with DJGPP @tab Scott Deifik, @EMAIL{scottd.mail@@sbcglobal.net,scottd dot mail at sbcglobal dot net}. -@cindex Zaretskii, Eli @item MS-Windows with MINGW @tab Eli Zaretskii, @EMAIL{eliz@@gnu.org,eliz at gnu dot org}. -@cindex Buening, Andreas @item OS/2 @tab Andreas Buening, @EMAIL{andreas.buening@@nexgo.de,andreas dot buening at nexgo dot de}. -@cindex Rankin, Pat -@cindex Malmberg, John @item VMS @tab Pat Rankin, @EMAIL{r.pat.rankin@@gmail.com,r.pat.rankin at gmail.com}, and John Malmberg, @EMAIL{wb8tyw@@qsl.net,wb8tyw at qsl.net}. -@cindex Pitts, Dave @item z/OS (OS/390) @tab Dave Pitts, @EMAIL{dpitts@@cozx.com,dpitts at cozx dot com}. @end multitable @@ -35116,7 +35736,7 @@ This @value{SECTION} briefly describes where to get them: @cindex Kernighan, Brian @cindex source code, Brian Kernighan's @command{awk} @cindex @command{awk}, versions of, See Also Brian Kernighan's @command{awk} -@cindex Brian Kernighan's @command{awk} +@cindex Brian Kernighan's @command{awk}, source code @item Unix @command{awk} Brian Kernighan, one of the original designers of Unix @command{awk}, has made his implementation of @@ -35136,6 +35756,7 @@ It is available in several archive formats: @uref{http://www.cs.princeton.edu/~bwk/btl.mirror/awk.zip} @end table +@cindex @command{git} utility You can also retrieve it from Git Hub: @example @@ -35155,7 +35776,7 @@ from GCC (the GNU Compiler Collection) works quite nicely. for a list of extensions in this @command{awk} that are not in POSIX @command{awk}. @cindex Brennan, Michael -@cindex @command{mawk} program +@cindex @command{mawk} utility @cindex source code, @command{mawk} @item @command{mawk} Michael Brennan wrote an independent implementation of @command{awk}, @@ -35201,7 +35822,7 @@ To get @command{awka}, go to @url{http://sourceforge.net/projects/awka}. The project seems to be frozen; no new code changes have been made since approximately 2003. -@cindex Beebe, Nelson +@cindex Beebe, Nelson H.F.@: @cindex @command{pawk} (profiling version of Brian Kernighan's @command{awk}) @cindex source code, @command{pawk} @item @command{pawk} @@ -35264,6 +35885,7 @@ This is an embeddable @command{awk} interpreter derived from @uref{http://repo.hu/projects/libmawk/}. @item @code{pawk} +@cindex source code, @command{pawk} (Python version) @cindex @code{pawk}, @command{awk}-like facilities for Python This is a Python module that claims to bring @command{awk}-like features to Python. See @uref{https://github.com/alecthomas/pawk} @@ -35369,6 +35991,7 @@ As @command{gawk} is Free Software, the source code is always available. @ref{Gawk Distribution}, describes how to get and build the formal, released versions of @command{gawk}. +@cindex @command{git} utility However, if you want to modify @command{gawk} and contribute back your changes, you will probably wish to work with the development version. To do so, you will need to access the @command{gawk} source code @@ -35544,6 +36167,7 @@ If possible, please update the @command{man} page as well. You will also have to sign paperwork for your documentation changes. +@cindex @command{git} utility @item Submit changes as unified diffs. Use @samp{diff -u -r -N} to compare @@ -35677,6 +36301,8 @@ coding style and brace layout that suits your taste. @node Derived Files @appendixsubsec Why Generated Files Are Kept In @command{git} +@c STARTOFRANGE gawkgit +@cindex @command{git}, use of for @command{gawk} source code @c From emails written March 22, 2012, to the gawk developers list. If you look at the @command{gawk} source in the @command{git} @@ -35856,7 +36482,7 @@ wget http://git.savannah.gnu.org/cgit/gawk.git/snapshot/gawk-@var{branchname}.ta @noindent to retrieve a snapshot of the given branch. - +@c ENDOFRANGE gawkgit @node Future Extensions @appendixsec Probable Future Extensions @@ -36227,8 +36853,15 @@ other introductory texts that you should refer to instead.) @cindex processing data At the most basic level, the job of a program is to process -some input data and produce results. See @ref{figure-general-flow}. +some input data and produce results. +@ifnotdocbook +See @ref{figure-general-flow}. +@end ifnotdocbook +@ifdocbook +See @inlineraw{docbook, <xref linkend="figure-general-flow"/>}. +@end ifdocbook +@ifnotdocbook @float Figure,figure-general-flow @caption{General Program Flow} @ifinfo @@ -36238,6 +36871,14 @@ some input data and produce results. See @ref{figure-general-flow}. @center @image{general-program, , , General program flow} @end ifnotinfo @end float +@end ifnotdocbook + +@docbook +<figure id="figure-general-flow"> +<title>General Program Flow</title> +<graphic fileref="general-program.eps"/> +</figure> +@end docbook @cindex compiled programs @cindex interpreted programs @@ -36253,9 +36894,15 @@ instructions in your program to process the data. @cindex programming, basic steps When you write a program, it usually consists -of the following, very basic set of steps, as shown -in @ref{figure-process-flow}: +of the following, very basic set of steps, +@ifnotdocbook +as shown in @ref{figure-process-flow}: +@end ifnotdocbook +@ifdocbook +as shown in @inlineraw{docbook <xref linkend="figure-process-flow"/>}: +@end ifdocbook +@ifnotdocbook @float Figure,figure-process-flow @caption{Basic Program Steps} @ifinfo @@ -36265,6 +36912,14 @@ in @ref{figure-process-flow}: @center @image{process-flow, , , Basic Program Stages} @end ifnotinfo @end float +@end ifnotdocbook + +@docbook +<figure id="figure-process-flow"> +<title>Basic Program Stages</title> +<graphic fileref="process-flow.eps"/> +</figure> +@end docbook @table @asis @item Initialization @@ -36435,7 +37090,7 @@ better written in another language. You can get it from @uref{http://awk.info/?awk100/aaa}. @cindex Ada programming language -@cindex Programming languages, Ada +@cindex programming languages, Ada @item Ada A programming language originally defined by the U.S.@: Department of Defense for embedded programming. It was designed to enforce good @@ -36503,9 +37158,6 @@ The GNU version of the standard shell @end ifinfo See also ``Bourne Shell.'' -@item BBS -See ``Bulletin Board System.'' - @item Bit Short for ``Binary Digit.'' All values in computer memory ultimately reduce to binary digits: values @@ -36580,11 +37232,6 @@ Changing some of them affects @command{awk}'s running environment. @item Braces See ``Curly Braces.'' -@item Bulletin Board System -A computer system allowing users to log in and read and/or leave messages -for other users of the system, much like leaving paper notes on a bulletin -board. - @item C The system programming language that most GNU software is written in. The @command{awk} programming language has C-like syntax, and this @value{DOCUMENT} @@ -36611,6 +37258,8 @@ The @uref{http://www.unicode.org, Unicode character set} is becoming increasingly popular and standard, and is particularly widely used on GNU/Linux systems. +@cindex Kernighan, Brian +@cindex Bentley, Jon @cindex @command{chem} utility @item CHEM A preprocessor for @command{pic} that reads descriptions of molecules @@ -36747,7 +37396,7 @@ ordinary expression. It could be a string constant, such as (@xref{Computed Regexps}.) @item Environment -A collection of strings, of the form @var{name@code{=}val}, that each +A collection of strings, of the form @var{name}@code{=}@code{val}, that each program has available to it. Users generally place values into the environment in order to provide information to various programs. Typical examples are the environment variables @env{HOME} and @env{PATH}. @@ -36916,7 +37565,7 @@ information about the name of the organization and its language-independent three-letter acronym. @cindex Java programming language -@cindex Programming languages, Java +@cindex programming languages, Java @item Java A modern programming language originally developed by Sun Microsystems (now Oracle) supporting Object-Oriented programming. Although usually @@ -37203,7 +37852,12 @@ record or a string. @c The GNU General Public License. @node Copying @unnumbered GNU General Public License +@ifnotdocbook @center Version 3, 29 June 2007 +@end ifnotdocbook +@docbook +<subtitle>Version 3, 29 June 2007</subtitle> +@end docbook @c This file is intended to be included within another document, @c hence no sectioning command or @node. @@ -37928,10 +38582,17 @@ first, please read @url{http://www.gnu.org/philosophy/why-not-lgpl.html}. @c The GNU Free Documentation License. @node GNU Free Documentation License @unnumbered GNU Free Documentation License +@ifnotdocbook +@center Version 1.3, 3 November 2008 +@end ifnotdocbook + +@docbook +<subtitle>Version 1.3, 3 November 2008</subtitle> +@end docbook + @cindex FDL (Free Documentation License) @cindex Free Documentation License (FDL) @cindex GNU Free Documentation License -@center Version 1.3, 3 November 2008 @c This file is intended to be included within another document, @c hence no sectioning command or @node. @@ -38436,8 +39097,10 @@ to permit their use in free software. @c ispell-local-pdict: "ispell-dict" @c End: +@ifnotdocbook @node Index @unnumbered Index +@end ifnotdocbook @printindex cp @bye @@ -38548,8 +39211,6 @@ Suggestions: % Next edition: % 1. Standardize the error messages from the functions and programs % in the two sample code chapters. -% 2. Nuke the BBS stuff and use something that won't be obsolete -% 3. Turn the advanced notes into sidebars by using @cartouche Better sidebars can almost sort of be done with: @@ -38581,4 +39242,3 @@ But to use it you have to say } which sorta sucks. - diff --git a/doc/texinfo.tex b/doc/texinfo.tex index b51ac3dc..7506dffb 100644 --- a/doc/texinfo.tex +++ b/doc/texinfo.tex @@ -3,7 +3,7 @@ % Load plain if necessary, i.e., if running under initex. \expandafter\ifx\csname fmtname\endcsname\relax\input plain\fi % -\def\texinfoversion{2014-02-09.15} +\def\texinfoversion{2014-03-18.17} % % Copyright 1985, 1986, 1988, 1990, 1991, 1992, 1993, 1994, 1995, % 1996, 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006, @@ -3935,19 +3935,23 @@ end } % multitable-only commands. -% -% @headitem starts a heading row, which we typeset in bold. -% Assignments have to be global since we are inside the implicit group -% of an alignment entry. \everycr resets \everytab so we don't have to +% +% @headitem starts a heading row, which we typeset in bold. Assignments +% have to be global since we are inside the implicit group of an +% alignment entry. \everycr below resets \everytab so we don't have to % undo it ourselves. \def\headitemfont{\b}% for people to use in the template row; not changeable \def\headitem{% \checkenv\multitable \crcr + \gdef\headitemcrhook{\nobreak}% attempt to avoid page break after headings \global\everytab={\bf}% can't use \headitemfont since the parsing differs \the\everytab % for the first item }% % +% default for tables with no headings. +\let\headitemcrhook=\relax +% % A \tab used to include \hskip1sp. But then the space in a template % line is not enough. That is bad. So let's go back to just `&' until % we again encounter the problem the 1sp was intended to solve. @@ -3978,15 +3982,15 @@ end % \everycr = {% \noalign{% - \global\everytab={}% + \global\everytab={}% Reset from possible headitem. \global\colcount=0 % Reset the column counter. - % Check for saved footnotes, etc. + % + % Check for saved footnotes, etc.: \checkinserts - % Keeps underfull box messages off when table breaks over pages. - %\filbreak - % Maybe so, but it also creates really weird page breaks when the - % table breaks over pages. Wouldn't \vfil be better? Wait until the - % problem manifests itself, so it can be fixed for real --karl. + % + % Perhaps a \nobreak, then reset: + \headitemcrhook + \global\let\headitemcrhook=\relax }% }% % @@ -4428,7 +4432,7 @@ end % complicated, when \tex is in effect and \{ is a \delimiter again. % We can't use \lbracecmd and \rbracecmd because texindex assumes % braces and backslashes are used only as delimiters. Perhaps we - % should define @lbrace and @rbrace commands a la @comma. + % should use @lbracechar and @rbracechar? \def\{{{\tt\char123}}% \def\}{{\tt\char125}}% % @@ -4449,8 +4453,7 @@ end % @end macro % ... % @funindex commtest - % - % The above is not enough to reproduce the bug, but it gives the flavor. + % This is not enough to reproduce the bug, but it gives the flavor. % % Sample whatsit resulting: % .@write3{\entry{xyz}{@folio }{@code {xyz@endinput }}} @@ -4663,6 +4666,9 @@ end \let\xeatspaces = \eatspaces } +% For testing: output @{ and @} in index sort strings as \{ and \}. +\newif\ifusebracesinindexes + % \indexnofonts is used when outputting the strings to sort the index % by, and when constructing control sequence names. It eliminates all % control sequences and just writes whatever the best ASCII sort string @@ -4691,11 +4697,16 @@ end % Unfortunately, texindex is not prepared to handle braces in the % content at all. So for index sorting, we map @{ and @} to strings % starting with |, since that ASCII character is between ASCII { and }. - \def\{{|a}% - \def\lbracechar{|a}% + \ifusebracesinindexes + \def\lbracechar{\lbracecmd}% + \def\rbracechar{\rbracecmd}% + \else + \def\lbracechar{|a}% + \def\rbracechar{|b}% + \fi + \let\{=\lbracechar + \let\}=\rbracechar % - \def\}{|b}% - \def\rbracechar{|b}% % % Non-English letters. \def\AA{AA}% |