Can the Linux ps command output be filtered by user AND command?

Question

I need the pid for a process given its owner and its command. I can filter a process per user with "ps -u xxx" and its command by "ps -C yyy", but when I try "ps -u xxx -C yyy", they are combined using OR logic. I need AND logic. How can I accomplish this?

Answer 1

Use pgrep?

pgrep -U xxx yyy

it returns just the pid (or pids, if more than one process matches).

Answer 2

Use grep?

ps -u xxx | grep yyy | grep -v grep

Answer 3

You use comm to find PIDs common to both conditions:

ps -u xxx | sort > /tmp/ps-uxxx
ps -C yyy | sort > /tmp/ps-Cyyy
comm -1 -2 /tmp/ps-uxxx /tmp/ps-Cyyy

Using bash, you can use process substitution to avoid the need for temporary files:

comm -1 -2 <(ps -u xxx | sort) <(ps -C yyy | sort)

Answer 4

A subtle refinement to the pgrep approach in the accepted answer (which I also upvoted).

When yyy happens to be a substring of another running command e.g. yyy is gnome-shell, we might get matches for gnome-shell-calendar-service as well. Point being, pgrep is good, but it doesn't completely answer the question (and is the reason I stopped using it).

By comparison, ps -C gnome-shell only returns matches for the gnome-shell process. I also hear @guettli's point about familiarity with commands. Your favorite sed or awk could be committed to muscle memory:

ps -fC gnome-shell | awk '($1=="the_user")'
ps -fC gnome-shell | sed -n '/^the_user\b/p'

If you just want the PID like pgrep, then awk can help:

ps -ouser=,pid= -C gnome-shell | awk '($1=="the_user"){print $2}'

You don't strictly need to replace -f with -o in the ps, but this post is about diminishing returns. If you need precise results, then this is your answer.

Answer 5

For the ones who need to achieve it on the fly (no script), here is a bit easier way.

ps -fp $(pgrep -d, -U theUser theCommand)