#!/usr/bin/perl

my $prog = shift || die "no args!\n";
my @pids;

open PH, "ps ax|" or die $!;

while( <PH> ){
        /$prog/ || next;
        /^\s*(\d+)/ and push @pids, $1
}

# Updated (thanks to merlyn):

kill 15, $_  for@pids;
sleep 5;
kill 2,  $_  for@pids;
sleep 5;
kill 9,  $_  for@pids;