Is there any other way to use tail -f for grep -q && operation?

Question

I found this solution: http://stackoverflow.com/questions/7178888/grep-q-not-exiting-with-tail-f

but is there any other possible?

UPD: I want to do tail -f | grep -q something && echo 'found!' but it doesn't work because tail -f prevents pipe from being closed, so echo command don't have a chance to be executed.

Answer 1

Try at your own risk:

tail -n 0 -f /tmp/bar | { grep -q -m1 zoo && echo found ; pkill -P $$ '^tail$' ; }

The pkill command is necesary if the match is in the last line. But may kill other tail process in background if any from the same parent.

Answer 2

I believe you want to use grep's -q or -m options. If you want to actually see the matching line, use -m1, which will print the line and exit (sending a SIGPIPE to tail, causing it to exit). If you don't care to see the line, use -q, which will just exit when it finds the first occurrence.