$pid = `pgrep -f '[a]bc'`;
...
until ($i > 60) {
	if ($pid) {
  	 $timestamp = localtime(time);
   	  print $fh ("$pid , $timestamp , $msg\n");
 	}else{
  	 $timestamp = localtime(time);
  	  print $fh ("No pid , $timestamp\n"); 
     }
$i = $i +1;
sleep 10;
	   $pid = `pgrep -f '[a]bc'`;
 }