$re = '/^(?:music|pictures)\/tom((?:\/(?:[\w-]+(?:[ ]+[\w-]+)*))*)(\/(?:[\w-]+(?:[ ]+[\w-]+)*))$/m';
$str = 'music/tom/foldername
music/tom/folder name
music/tom/abc/foldername/folder2';
preg_match_all($re, $str, $matches, PREG_SET_ORDER, 0);
// Print the entire match result
var_dump($matches);
Please keep in mind that these code samples are automatically generated and are not guaranteed to work. If you find any syntax errors, feel free to submit a bug report. For a full regex reference for PHP, please visit: http://php.net/manual/en/ref.pcre.php