$re = '/e(?:pisode)?\s*(\d{1,3}(?!\d)|\d\d\d??)(?:-?e?(\d{1,3}))?(?!\d)/m';
$str = 'some.random.tv.show.s01episode01.1080p
some.random.tv.show.s01episode 01.1080p
some.random.tv.show.s01episode1.1080p
some.random.tv.show.s01episode 1.1080p
some.random.tv.show.s01e01.1080p
some.random.tv.show.s01e1.1080p
some.random.tv.show.s01e0102.1080p
some.random.tv.show.s01e01-02.1080p
some.random.tv.show.s01e01e02.1080p
some.random.tv.show.s01e01-e02.1080p
some.random.tv.show.s01e199.1080p
some.random.tv.show.s01e001004.1080p
some.random.tv.show.s01e1-e2.1080p
some.random.tv.show.s01e001-e002.1080p';
preg_match_all($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