Here is a simple example to find PID of ssh-agent for current user without showing PID of grep process itself :
ps xu | grep "${USER}.*[ ]/usr/bin/ssh-agent" | awk '{print $1 $2;}' If you want for example to kill ssh-agent for current user you might use following command :
kill `ps xu | grep "${USER}.*[ ]/usr/bin/ssh-agent" | awk '{print $2;}'` P.S. I've only tested these commands on Ubuntu