检测文件是否有BOM 头，并删除BOM头（php）

将下面文件放在网站根目录访问即可，它会遍历当前目录下所有子目录，检测文件是否含有BOM头，并删除BOM头

<?php
//remove the utf-8 boms
//by magicbug at gmail dot com
set_time_limit(0);

if (isset($_GET['dir'])){ //config the basedir
$basedir=$_GET['dir'];
}else{
$basedir = '.';
}
$auto = 1;
checkdir($basedir);
function checkdir($basedir){
if ($dh = opendir($basedir)) {
  while (($file = readdir($dh)) !== false) {
   if ($file != '.' && $file != '..'){
    if (!is_dir($basedir."/".$file)) {
     echo "filename: $basedir/$file ";
     echo checkBOM("$basedir/$file")." <br>";
    }else{
     $dirname = $basedir."/".$file;
     checkdir($dirname);
    }
   }
  }
closedir($dh);
}
}
function checkBOM ($filename) {
global $auto;
$contents = file_get_contents($filename);
$charset[1] = substr($contents, 0, 1);
$charset[2] = substr($contents, 1, 1);
$charset[3] = substr($contents, 2, 1);
if (ord($charset[1]) == 239 && ord($charset[2]) == 187 && ord($charset[3]) == 191) {
  if ($auto == 1) {
   $rest = substr($contents, 3);
   rewrite ($filename, $rest);
   return ("<font color=red>BOM found, automatically removed.</font>");
  } else {
   return ("<font color=red>BOM found.</font>");
  }
}
else return ("BOM Not Found.");
}
function rewrite ($filename, $data) {
$filenum = fopen($filename, "w");
flock($filenum, LOCK_EX);
fwrite($filenum, $data);
fclose($filenum);
}
?>