> Replace "foo.txt" with a user supplied variable, let's call it "$F". It becomes cat $F | blah_blah... I mean cat "$F" | blah_blah, first trap, but everyone kn

> Replace "foo.txt" with a user supplied variable, let's call it "$F". It becomes cat $F | blah_blah... I mean cat "$F" | blah_blah, first trap, but everyone knows that. I think that you forgot to edit the "I mean" to "echo $F" :)