$re = '/(0[1-9]|[12][0-9]|3[01]):(0[1-9]|1[012]):(\d{1,4})\s+([0-1][0-9]|2[0-3]):([0-5][0-9])\s+-\s+(\w{2})/m';
$str = '21:10:1999 12:12 - ss
01:10:1999 12:12 - ss
01:10:1999 23:59 - ss
01:10:1999 00:59 - ss
01:10:1999 00:61 - ss
';
preg_match_all($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