Usage example:
<?php
$path = realpath('/etc');
$objects = new RecursiveIteratorIterator(new RecursiveDirectoryIterator($path), RecursiveIteratorIterator::SELF_FIRST);
foreach($objects as $name => $object){
echo "$name\n";
}
?>
This prints a list of all files and directories under $path (including $path ifself). If you want to omit directories, remove the RecursiveIteratorIterator::SELF_FIRST part.