kill [-pgroup] [signal] idlist
Sends a signal to each process in the list idlist,
if permitted. signal, if present, is the signal number or
the symbolic name of the signal; see
signal(S) for details. The
leading SIG is optional when the signal is specified by
its symbolic name. The default for signal is 15,
SIGTERM.
If -pgroup is specified, the numbers in idlist are taken as process group IDs and the signal is sent to all of the processes in that process group. A process group ID of 0 specifies the current process group.