gawk: option requires an argument -- f
Gnu Awk (gawk) 2.15, patchlevel 3
Usage: gawk [POSIX or GNU style options] -f progfile [--] file ...
	gawk [POSIX or GNU style options] [--] 'program' file ...
POSIX options:		GNU long options:
	-f progfile		--file=progfile
	-F fs			--field-separator=fs
	-v var=val		--assign=var=val
	-W compat		--compat
	-W copyleft		--copyleft
	-W copyright		--copyright
	-W help			--help
	-W lint			--lint
	-W posix		--posix
	-W source=program-text	--source=program-text
	-W usage		--usage
	-W version		--version