diff options
| -rw-r--r-- | pw.1 | 37 | ||||
| -rw-r--r-- | pw.c | 19 |
2 files changed, 49 insertions, 7 deletions
@@ -30,7 +30,7 @@ pw \- Pipe Watch: monitor recent lines of output from pipe .SH SYNOPSIS -command | pw [-i interval] [-l interval] [-n number-of-lines] [-d] +command | pw [-i interval] [-l interval] [-n number-of-lines] [-dEB] .SH DESCRIPTION .I pw @@ -210,7 +210,8 @@ the top of the display. In tail trigger mode, the status string appears, showing the pattern preceded by a question mark. The .I pattern -is an extended regular expression (ERE). +is interpreted as either an extended regular expression (ERE) +or (BRE) depending on the current setting. Trigger patterns saved in a history which may be navigated for recall using the up and down arrow keys or .B Ctrl-P @@ -271,7 +272,7 @@ pattern onto the grep stack. The command pushes a plain pattern; the .B :v command pushes a logically inverted pattern. The grep stack holds up to 64 -patterns, which are extended regular expressions (EREs). +patterns. If the pattern is successfully pushed onto the stack, it restricts which lines are admitted into the FIFO and available for display. The plain pattern admits only the lines which match @@ -318,7 +319,18 @@ command option for the argument format and the option for the semantics. .PP -Any other command results in a brief error message. +.IP "\fB:E\fP, \fB:B\fP" +Enable extended regular expressions (EREs) or basic regular expressions (BREs), +respectively. If no +.B -E +option is given to the program, then BRE mode is in effect on start up. +This setting does not affect the meaning of patterns that are currently in +effect in the grep stack or in the trigger. The setting affects new patterns +that will subsequently be presented to the program. Note that the currently +active patterns shown in the status line are not accompanied by any indication +of whether they were compiled as ERE or BRE. + +Any other command string results in a brief error message. .SH OPTIONS @@ -369,6 +381,23 @@ and staying in the interactive mode. This is useful when the last portion of the input is of interest, and contains long lines that require horizontal scrolling. +.IP \fB-E\fP +Enable extended regular expressions (EREs). By default, regular expressions +processed by +.I pw +are treated as basic regular expressions (BREs). The mode can be switched +at run time using the +.B :E +and +.B :B +commands. + +.IP \fB-B\fP +Disable extended regular expressions (EREs), switching to basic (BREs). Since +that is the default, this option has no effect unless it appears after a +.B -E +option. + .SH TERMINATION STATUS If @@ -60,6 +60,7 @@ typedef struct dstr { static int poll_interval = 1000; static int long_interval = 10000; +static int regex_flags = 0; static char **snapshot; static int snaplines; @@ -470,7 +471,7 @@ static void execute(char *cmd, unsigned *pstat) memset(gr, 0, sizeof *gr); - if ((err = regcomp(&gr->rx, arg, REG_EXTENDED | REG_NOSUB)) != 0) { + if ((err = regcomp(&gr->rx, arg, regex_flags | REG_NOSUB)) != 0) { regerror(err, &gr->rx, cmd, cmdsize); break; } @@ -510,6 +511,12 @@ static void execute(char *cmd, unsigned *pstat) dsdrop(err); } break; + case 'E': + regex_flags = REG_EXTENDED; + break; + case 'B': + regex_flags = 0; + break; default: sprintf(cmd, "bad command"); break; @@ -574,7 +581,7 @@ int main(int argc, char **argv) if (ttyfd < 0) panic("unable to open /dev/tty"); - while ((opt = getopt(argc, argv, "n:i:l:d")) != -1) { + while ((opt = getopt(argc, argv, "n:i:l:dEB")) != -1) { switch (opt) { case 'n': { @@ -604,6 +611,12 @@ int main(int argc, char **argv) case 'd': auto_quit = 0; break; + case 'E': + regex_flags = REG_EXTENDED; + break; + case 'B': + regex_flags = 0; + break; default: usage(argv[0]); } @@ -951,7 +964,7 @@ int main(int argc, char **argv) int err; trigpat = dsdup(cmdbuf + 1); if ((err = regcomp(&trigex, trigpat, - REG_EXTENDED | REG_NOSUB))) + regex_flags | REG_NOSUB))) { regerror(err, &trigex, cmdbuf, sizeof cmdbuf); if (columns < (int) sizeof cmdbuf - 1) |