$re = '/([0-2]\d:[0-5][0-9]\-[0-2]\d:[0-5][0-9])/';
$str = '- von 08:00-12:00uhr und 12:00-22:00 uhr
- von 08:00-12:00 uhr
- von 08:00-12:00 uhr
- von 08:00-12:00
- 08:00-12:00';
preg_match_all($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