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OK, total noob question here. Could we achieve the same thing with something like pgrphack from daemontools?

    pgrphack sh -c "processes"
Kill the pid for the sh ("agent") and you thereby kill all the processes?

Again, sorry for the noob question. I'm still learning and making mistakes.



No. To instruct kill() to kill a process group, you have to specified the PID of the process group leader as a negative number. Otherwise kill() will kill only a single process.


But won't all the processes in my example have the PGID of sh?


Yes they do, but that is irrelevant. kill(pid) kills the process specified by 'pid'. kill(-pid) kills the process group specified by 'pid'.


What if I just use userland kill(1) utility? Is it possible to kill all processes under a PGID using kill(1)?

Say the PGID I get for sh is 321. If I do

    kill [signal] 321
that will not kill all the processes having PGID 321?

If it would not kill them, then couldn't we modify kill(1) to be able to call kill() with a negative integer as you describe?

Sorry for the noob questions. I am still learning and making mistakes.




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