"killall - kill all active processes killall is used by shutdown (1M) to kill all active processes not directly related to the shutdown procedure "
So, intended for use by shutdown(1M) and nothing else. It's basically a completely different utility to the Linux one. They just happen to, unfortunately, share the same name.
So, intended for use by shutdown(1M) and nothing else. It's basically a completely different utility to the Linux one. They just happen to, unfortunately, share the same name.