$re = '/\b([\w\-+()\' .,]+(?:\[[\w\-\/+()\' .,]*\][\w\-+()\' .,]*)*\.[A-Za-z0-9]{2,4})\b/';
$str = 'Subject-KrzpfTest [02/30] - ""KrzpfTest.part.nzb"" yEnc
[PRiVATE]-[WtFnZb]-[Supertje-_S03E11-12_-blabla_+_blabla_WEBDL-480p.mkv]-[4/12] - "" yEnc 9786 (1/1366)
[N3wZ] MAlXD245333\\\\::[PRiVATE]-[WtFnZb]-[Show.S04E04.720p.AMZN.WEBRip.x264-GalaxyTV.mkv]-[1/2] - "" yEnc 293197257 (1/573)
Singer - A Album (2005) - [04/25] - 02 Sweetest Somebody (I Know).flac
[PRiVATE]-[WtFnZb]-[00000.clpi]-[1/46] - "" yEnc 788 (1/1)
[PRiVATE]-[WtFnZb]-[/More.Bla.S02E01.1080p.WEB.h264-EDITH[eztv.re].mkv] yEnc 2990558544 (1/4173)
';
preg_match_all($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