I have two Tomcat processes, one is called event-ws, another is called app-event-ws. I sometimes need to kill event-ws from a shell script:
ps -ef | grep -w event-ws | grep -v grep
The above will find and kill both of them; how can I find exactly find one of them?
pgrep / pkill are the best tools to use in this case, instead of ps:
pgrep -x event-ws # match by executable filename 'event-ws'; print PID
pkill -x event-ws # match and kill
Each command matches process(es) whose executable filename is event-ws exactly (-x) (irrespective of whether a directory path prefix was used when the executable was launched).
Note, however, that your pgrep / pkill implementation may limit the name to 15 characters - both when matching and in its output.
pgrep simply prints the matching PID(s) (process ID(s)), whereas pkill kills the matching process(es).
If, by contrast, you need to match by a part of the full command line, use the -f option with a regular expression:
pgrep -f '/event-ws/' # match by part of the full command line; print PID and name
pkill -f '/event-ws/' # match and kill
If you add -l to the pgrep command, the full command line of matching process(es) is printed instead of just the process name.