bash: sleep process not getting killed [duplicate]

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?

Answer 1

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.

Answer 2

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`