Usage: SET NOTIFY_ON_TERMINATION [ON|OFF|TOGGLE]
  When ON, all EXEC'ed processes will inform you when they exit.
  You will be told which process is exiting and the reason it
  exited.  If termination was normal, you will receive the exit
  status code.  If termination was by signal, you will be told
  which signal.  If OFF, you will not be informed when processes
  exit.