What's tripping you up is that some processing is being done by the shell before grep ever sees your pattern. Taking that into account, what grep is seeing is:
songbird <songb...@anthive.com> writes: > me@ant(25)$ env | grep -F "-g" grep -F -g > grep: invalid option -- 'g' > Usage: grep [OPTION]... PATTERN [FILE]... > Try 'grep --help' for more information. > me@ant(26)$ env | grep -F '-g' grep -F -g > grep: invalid option -- 'g' > Usage: grep [OPTION]... PATTERN [FILE]... > Try 'grep --help' for more information. > me@ant(27)$ env | grep -F 'CFL' > CFLAGS=-g grep -F CFL > me@ant(28)$ env | grep '\-g' > CFLAGS=-g grep \-g (I'll note that in this case you need the quotes or the shell would have stripped the \ . I'm guessing this one is doing what you want) > me@ant(29)$ env | grep '-g' grep -g > grep: invalid option -- 'g' > Usage: grep [OPTION]... PATTERN [FILE]... > Try 'grep --help' for more information. > me@ant(30)$ env | grep "-g" grep -g > grep: invalid option -- 'g' > Usage: grep [OPTION]... PATTERN [FILE]... > Try 'grep --help' for more information. > > > songbird
