PHP去除重复图片文件的代码

/**
* 去除重复的图片文件
* by bbs.it-home.org
*/
exec("find . -type f", $lines);
$arr = array();
$del = array();
$n = 0;
foreach($lines as $line){
 $line = trim($line);
 if(!$line){
  continue;
 }
 $n ++;
 $md5 = md5_file($line);
 if(isset($arr[$md5])){
  $del[] = $line;
  //echo "$n del $line\n";
  unlink("{$line}");
 }else{
  $arr[$md5] = 1;
 }
}
echo "del " . count($del) . " files\n";
//echo join("\n", $del);