kill ?-pgroup ?signal? idlist
              Send  a  signal  to  the  each  process in the list
              idlist, if permitted.  Signal, if present,  is  the
              signal  number  or the symbolic name of the signal,
              see the signal system call manual page.  The  lead-
              ing  ``SIG''  is optional when the signal is speci-
              fied by its symbolic name.  The default  for  signo
              is 15, SIGTERM.

              If  -pgroup is specified, the numbers in idlist are
              take as process group ids and the signal is sent to
              all  of  the process in that process group.  A pro-
              cess group id of 0 specifies  the  current  process
              group.

              This command is provided by Extended Tcl.