$re = '/99_\w{3}_(A|B)_((X|(?>YZ))(0*[1-9][0-9]?)_(FOO|BAR) \3Y?-(\b0?20(1[4-9]|[2-9][0-9])\b)-\b0?((?:[1-9]|1[0-2])|(?:[4]|1[0]))\b$)/m';
$str = '99_GOG_A_X1_FOO X-2014-09
99_YAK_A_YZ1_BAR YZY-2014-10
99_YAK_A_YZ1_BAR YZY-2014-11
99_GOG_A_X1_FOO X-2014-13
99_YAK_A_X1_BAR YZY-2014-10
99_GOG_A_YZ1_FOO X-2014-10
99_GOG_A_X1_FOO X-2014-11';
preg_match_all($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