=over =item kill SIGNAL, LIST X X Sends a signal to a list of processes. Returns the number of processes successfully signaled (which is not necessarily the same as the number actually killed). $cnt = kill 1, $child1, $child2; kill 9, @goners; If SIGNAL is zero, no signal is sent to the process, but the kill(2) system call will check whether it's possible to send a signal to it (that means, to be brief, that the process is owned by the same user, or we are the super-user). This is a useful way to check that a child process is alive (even if only as a zombie) and hasn't changed its UID. See L for notes on the portability of this construct. Unlike in the shell, if SIGNAL is negative, it kills process groups instead of processes. (On System V, a negative I number will also kill process groups, but that's not portable.) That means you usually want to use positive not negative signals. You may also use a signal name in quotes. See L for more details. =back