I am writing one shell script in which I have parent process and it has child processes which are created by sleep &
command. Now I wish to kill the parent process so that the child process will be also killed. I was able to do that this with below command:
trap "kill $$" SIGINT
trap 'kill -HUP 0' EXIT
trap 'kill $(jobs -p)' EXIT
These commands are working with kill [parent_process_ID]
commands but if I use kill -9 [parent_process_ID]
then only the parent process will be killed.
Please guide me further to achieve this functionality so that when I kill parent process with any command then child process should be also killed.
When you kill a process alone, it will not kill the children.
You have to send the signal to the process group if you want all processes for a given group to receive the signal.
kill -9 -parentpid
Otherwise, orphans will be linked to init
.
Child can ask kernel to deliver SIGHUP
(or other signal) when parent dies by specifying option PR_SET_PDEATHSIG
in prctl()
syscall like this:
prctl(PR_SET_PDEATHSIG, SIGHUP);
See man 2 prctl
for details.