$rnumber = int(rand("100"));
  if (-e $file.".bak".$rnumber) {
  	$origi = $file.".bak".$rnumber;
  	while ($origi == $file.".bak".$rrnumber) {
  		$rrnumber = int(rand("100"));
  	}
  	$newfile = $file.".bak".$rrnumber;
  	move($file,$newfile);
  }
  else {
  	$newfile = $file.".bak".$rnumber;
  	move($file,$newfile);
  }