Piping PIDs into kill doesn't work

Question

I'm fighting a bug in IntelliJ where nailgun instances screw up when SNAPSHOT dependencies are updated. I want to automate killing all processes that contain nailgun in their name.

So far I can get all relevant PIDs like so:

ps -x -o pid,cmd | grep nailgun | cut -f 1 -d ' '

This gives me for example:

I can go and run kill for each of them manually, like kill 26759 etc. But piping doesn't work:

ps -x -o pid,cmd | grep nailgun | cut -f 1 -d ' ' | kill

This just prints

kill: usage: kill [-s sigspec | -n signum | -sigspec] pid | jobspec ... or kill -l [sigspec]

How do I pipe the list of PIDs to kill?

0__ · Answer 1 · 2017-06-11T15:18:39.527

3

Putting the PIDs onto one line with xargs works:

ps -x -o pid,cmd | grep nailgun | cut -f 1 -d ' ' | xargs kill

The only annoyance is that this prints kill: (xyz): No such process for the grep instance which shows up in the ps list as well.

Another alternative:

pgrep -f nailgun | xargs kill

edited Jun 11 '17 at 15:18

answered Jun 11 '17 at 15:12

0__

684

6

If you’re going to use pgrep, you might as well use pkill. – Stephen Kitt Jun 11 '17 at 15:22
It works better because kill doesn't read stdin; it wants the pids as args, which xargs does. – Jeff Schaller Jun 11 '17 at 15:58
See also whereis, pipeline and ls. – Stephen Kitt Jun 11 '17 at 17:52
You could also just add another grep to filter our 'grep' in the results e..g ps -x -o pid,cmd | grep nailgun | grep -v 'grep' | cut -f 1 -d ' ' | xargs kill. FYI for me I had to cut -f 2 -d ' ' as well. – mrjamesmyers Jan 04 '19 at 11:13

Piping PIDs into kill doesn't work

1 Answers1