bash Cookbook

Grepping ps Output Without Also Getting the grep Process Itself

Problem

You want to grep output from the ps command without also getting the grep process itself.

Solution

Change the pattern you are looking for so that it is a valid regular expression that will not match the literal text that ps will display:

$ ps aux | grep 'ssh'
root   366  0.0  1.2  340  1588 ?? Is   20Oct06  0:00.68 /usr/sbin/sshd
root 25358  0.0  1.9  472  2404 ?? Ss   Wed07PM  0:02.16 sshd: root@ttyp0jp   27579  0.0  0.4  152   540 p0 S+    3:24PM  0:00.04 grep ssh

$ ps aux | grep '[s]sh'
root   366  0.0  1.2  340  1588 ?? Is   20Oct06  0:00.68 /usr/sbin/sshd
root 25358  0.0  1.9  472  2404 ?? Ss   Wed07PM  0:02.17 sshd: root@ttyp0

Discussion

This works because [s] is a regular expression character class containing a single lowercase letter s, meaning that [s]sh will match ssh but not the literal string grep [s]sh that ps will display.

The other less efficient and more clunky solution you might see is something like this:

$ ps aux | grep 'ssh' | grep -v grep

See Also

• man ps

• man pgrep

• man grep