Are you sure about that, what if file contains the equal sign? $ touch foo=bar $ file foo=bar foo=bar: empty $ awk '/bar/ { print $1 | "sort -u"}' foo=

Are you sure about that, what if file contains the equal sign? $ touch foo=bar $ file foo=bar foo=bar: empty $ awk '/bar/ { print $1 | "sort -u"}' foo=bar bar screw this! ^D bar $ awk '/bar/ { print $1 | "sort -u"}' <foo=bar $