I'm doing a pretty standard
tail -f some_log_file.txt | grep -q known-string
If I run the command without the
tail -f some_log_file.txt | grep known-string
I see output:
[Tue Feb 12 11:32:45 2019] known-string.
so I know the grep is matching. However when I add
-q the grep command doesn't exit, it just hangs there waiting for more output ... even though the man page says it will "Exit immediately with zero status if any match is found":
-q, --quiet, --silent Quiet; do not write anything to standard output. Exit immediately with zero status if any match is found, even if an error was detected. Also see the -s or --no-messages option.
Can anyone explain why
-q isn't causing my grep to exit? I'm trying to chain a
&& beep to the end so the
grep beeps when a match is found, but unless I can make it exit that won't work.