$re = '/^\h*(?:(?:\*|[0-9]+)\/0*(?:[0-4]))(?:\s+\*){4}/m';
$str = '2,5,8,27,30,36,12,15,18,21,24,39,42 * * * * /bin/echo 0
5,5,8,27,30,36,12,15,18,21,24,39,42 * * * * /bin/echo 0
200,5,8,27,30,36,12,15,18,21,24,39,42 * * * * /bin/echo 0
27,30,36,12,15,18,21,24,39,42 * * * * /bin/echo 0
*/16 * * * * /bin/echo 0
*/13 * * * * /bin/echo 0
*/4 * * * * /bin/echo 0
*/2 * * * * /bin/echo 0
*/3 * * * * /bin/echo 0
110,5,8,27,30,36,12,15,18,21,24,39,42 * * * * /bin/echo 0
';
preg_match_all($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