Perl Programming/Keywords/kill

The kill keyword

The kill command sends a signal to a LIST of processes. Returns the number of arguments that were successfully used to signal. This is not necessarily the same as the number of processes actually killed, as a process group can also be killed. SIGNAL is either a name of a signal, or a signal number.

If the signal name is negative, it is the same as a negative number and kills a group of processes.

If SIGNAL is either 0, the string SIGZERO, or ZERO, no signal is sent to the process, but the command checks whether it's possible to send a signal to it. This is useful to check that a child process is still alive with the same UID.

Syntax

  kill SIGNAL, LIST
  kill SIGNAL

Examples

  $cnt = kill 'HUP', $child1, $child2;
  kill 'KILL', @goners;
  kill '-KILL', $processes;  # same as next line
  kill -9, $processes;       # same as previous line