gawk: option requires an argument -- f
Usage: gawk [POSIX or GNU style options] -f progfile [--] file ...
Usage: gawk [POSIX or GNU style options] [--] 'program' file ...
POSIX options:		GNU long options: (standard)
	-f progfile		--file=progfile
	-F fs			--field-separator=fs
	-v var=val		--assign=var=val
Short options:		GNU long options: (extensions)
	-b			--characters-as-bytes
	-c			--traditional
	-C			--copyright
	-d[file]		--dump-variables[=file]
	-D[file]		--debug[=file]
	-e 'program-text'	--source='program-text'
	-E file			--exec=file
	-g			--gen-pot
	-h			--help
	-i includefile		--include=includefile
	-I			--trace
	-l library		--load=library
	-L[fatal|invalid|no-ext]	--lint[=fatal|invalid|no-ext]
	-M			--bignum
	-N			--use-lc-numeric
	-n			--non-decimal-data
	-o[file]		--pretty-print[=file]
	-O			--optimize
	-p[file]		--profile[=file]
	-P			--posix
	-r			--re-interval
	-s			--no-optimize
	-S			--sandbox
	-t			--lint-old
	-V			--version

To report bugs in Enhanced Gawk, send e-mail to 
Kaz Kylheku <kaz at kylheku dot com>.
PLEASE do NOT try to report bugs or seek support in the original
bug-gawk mailing list, unless you can reproduce the issue with the
unmodified gawk program. Also do not report bugs in the comp.lang.awk
Usenet newsgroup, or in web forum such as Stack Overflow.

gawk is a pattern scanning and processing language.
By default it reads standard input and writes standard output.

Examples:
	gawk '{ sum += $1 }; END { print sum }' file
	gawk -F: '{ print $1 }' /etc/passwd