例01：

<?PHP
  // read all files inside the given directory
  // limited to a specific file extension
  $files = glob("./ABC/*.txt");
?>

例02：

<?PHP
  // perform actions for each file found
  foreach (glob("./ABC/*.txt") as $filename) {
    echo "$filename size " . filesize($filename) . "\n";
  }
?>

例03：使用RecursiveIteratorIterator

<?PHP 
foreach(new RecursiveIteratorIterator( new RecursiveDirectoryIterator("../")) as $file) {
  if (strtolower(substr($file,-4)) == ".txt") {
        echo $file;
  }
}
?>