bash: sleep process not getting killed

Question

I wrote a simple bash script which does nothing but sleeps.

#!/bin/bash

echo "Sleeping..."
sleep 180s

I see two processes running on my system after I run the script:

user 22880  0.0  0.0  12428  1412 pts/28   S+   20:12   0:00 /bin/bash ./sleep.sh
user 22881  0.0  0.0   7196   356 pts/28   S+   20:12   0:00 sleep 180s

I give a SIGTERM to the process with id 22880 by using kill -15 22880 which kills the process. However, after this, I still see the sleep command running which exits after 180 seconds.

user 22881  0.0  0.0   7196   356 pts/28   S    20:12   0:00 sleep 180s

Why does this happen? What do I need to do to not leave the sleep 180s process running?

weird... I tried your script (with sh and ./) ps -aux doesn't return anything anymore after kill -15 of the process number, how do you display the list of process, with ps -aux ? — Anyone_ph, Dec 23 '15 at 15:00
Yes. I did a `ps aux | grep sleep`. The process still remains even if I give a `SIGKILL`. — akaHuman, Dec 23 '15 at 15:02
Ok I understand now, this is the process of grep not your script, try ps -aux |grep idontexist :) — Anyone_ph, Dec 23 '15 at 15:04
@Anyone_ph Not sure if that is true. The grep process comes as: `user 22887 0.0 0.0 11744 912 pts/29 S+ 20:13 0:00 grep --color=auto sleep` which is different than the `sleep 180s` process. — akaHuman, Dec 23 '15 at 15:07

score 12 · Accepted Answer · answered Dec 23 '15 at 15:05

kill -15 22880 will send a signal to the shell executing the script, but not the sleep command. To send the signal to every process in the process group, you should be able to specify a negative process ID.

kill -15 -22880

Alternately, ensure that the script kills its children before exiting.

trap 'kill $(jobs -p)' EXIT
echo "Sleeping..."
sleep 180s & wait

If you leave sleep in the foreground when the signal is received, the shell must wait until it exits before running the trap; sleep is uninterruptible. The workaround is to run it in the background, then wait on it. wait, being a shell built-in, can be interrupted, so that the trap runs immediately and kills any background processes still in progress.

This is a good reference that explains what you have said: http://riccomini.name/posts/linux/2012-09-25-kill-subprocesses-linux-bash/ — Explosion Pills, Dec 23 '15 at 15:11

score 1 · Answer 2 · edited Feb 13 '19 at 13:42

you can also use killall sleep or kill -9/15 $(pidof sleep)

9 use to kill the process and 15 use to terminate the process

bash$ ps -ef|grep sleep
pratik   24775  2695  0 23:44 pts/0    00:00:00 sleep 600
pratik   24778 24690  0 23:44 pts/29   00:00:00 grep --color=auto sleep
bash$ killall sleep 
bash$ ps -ef|grep sleep
pratik   24792 24690  0 23:44 pts/29   00:00:00 grep --color=auto sleep
bash$
bash$ ps -ef|grep sleep
pratik   24978  2695  0 23:52 pts/0    00:00:00 sleep 600
pratik   24981 24690  0 23:52 pts/29   00:00:00 grep --color=auto sleep
bash$ kill -15 $(pidof sleep)
bash$ ps -ef|grep sleep
pratik   24986 24690  0 23:52 pts/29   00:00:00 grep --color=auto sleep`

bash: sleep process not getting killed

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