    Send a signal to a job.
    
    Send the processes identified by PID or JOBSPEC the signal named by
    SIGSPEC or SIGNUM.  If neither SIGSPEC nor SIGNUM is present, then
    SIGTERM is assumed.
    
    Options:
      -s sig	SIG is a signal name
      -n sig	SIG is a signal number
      -l	list the signal names; if arguments follow `-l' they are
    	assumed to be signal numbers for which names should be listed
    
    Kill is a shell builtin for two reasons: it allows job IDs to be used
    instead of process IDs, and allows processes to be killed if the limit
    on processes that you can create is reached.
    
    Exit Status:
    Returns success unless an invalid option is given or an error occurs.
