Killing process + perl

#!/usr/bin/perl

@s=`ps aux`;

if(! $ARGV[0] )
    {
    print "Pass the arguement \n\n USAGE: pk processname (ex: firefox)\n";
    exit;
    }

foreach $i (@s)
    {
    if(($i=~/$ARGV[0]/i)&&($i!~m/processkill/i))
        {
        print "Killing $ARGV[0] Process\n";
        @processlist=split(" ",$i);
        system("kill -9 $processlist[1]");
        }
    }




scriptname process_name_to_kill (eg firefox )