$re = '/(http[s]{0,1}:\/\/localhost:[0-9]{4}\/flight\/)|(http[s]{0,1}:\/\/localhost:[0-9]{4}\/f\/)/';
$str = '1.http://localhost:9001/f/
2.http://localhost:9001/flight/
http[s]{0,1}:\\/\\/localhost:[0-9]{4}\\/f\\/
http[s]{0,1}:\\/\\/localhost:[0-9]{4}\\/flight\\/';
preg_match_all($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