Unix Termination Signals

by Jared Beck

I've always heard that kill and kill -9 send different signals but I never knew the details.  The The GNU C Library has a good reference of the  termination signals, and man -S 1 kill explains the numbers.

Running kill with no arguments sends SIGTERM. kill -1 sends SIGHUP.  Hitting ctrl-C, or kill -2 sends SIGINT.  kill -3 sends SIGQUIT.  Finally, kill -9 sends SIGKILL, which "cannot be handled or ignored".

I suppose for the real nitty-gritty on kill and termination signals, you should check out IEEE Std 1003.2 ("POSIX.2").

Happy hacking ♥ -Jared