News for hackers. Stuff that matters.

A comment on The right way to deal with frozen processes on Unix. Parent comment

Re:The right way to deal with frozen processes on Unix by FooBarWidget on Saturday September 22, 2012 @07:12AM (#4557618)
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.
[ Parent | on HN ]
Re:The right way to deal with frozen processes on Unix by unixnoob on Sunday September 23, 2012 @04:04AM (#4560367)
But won't all the processes in my example have the PGID of sh?
[ Parent | on HN ]
Re:The right way to deal with frozen processes on Unix by FooBarWidget on Sunday September 23, 2012 @02:49PM (#4561687)
Yes they do, but that is irrelevant. kill(pid) kills the process specified by 'pid'. kill(-pid) kills the process group specified by 'pid'.
[ Parent | on HN ]
Re:The right way to deal with frozen processes on Unix by unixnoob on Sunday September 23, 2012 @04:48PM (#4561985)
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.

[ Parent | on HN ]