## pseudocode, so won't do any good as it is
   if( $i_am_the_child ) {
      setpgrp();
      `some_cmd`;
   } else {
      ## parent
      sleep $sleepamt;

      ## I think 15 is SIGTERM. please confirm on
      ## on your system
      kill -15, getpgrp( $child_pid );
   }