SUPERVISOR.PL
-------------
  print PIDFILE "$$\r\n";

  $SIG{QUIT} = \%SHUTDOWN;

  fork()
  if child, exec ctrlman.pl
  fork()
  if child, exec pidman.pl
  fork()
  if child, exec progman.pl
  fork()
  if child, exec webman.pl
  while (1) {
    do stuff
  }
  exit;

  sub SHUTDOWN {
    kill 3, CTRLMAN_pid   # pid saved from the fork
    kill 3, PIDMAN_pid
    kill 3, PROGMAN_pid
    kill 3, WEBMAN_pid
  }