$re = '/^\\\\s*($|#|\\\\w+\\\\s*=|(\\\\?|\\\\*|(?:[0-5]?\\\\d)(?:(?:-|\/|\\\\,)(?:[0-5]?\\\\d))?(?:,(?:[0-5]?\\\\d)(?:(?:-|\/|\\\\,)(?:[0-5]?\\\\d))?)*)\\\\s+(\\\\?|\\\\*|(?:[0-5]?\\\\d)(?:(?:-|\/|\\\\,)(?:[0-5]?\\\\d))?(?:,(?:[0-5]?\\\\d)(?:(?:-|\/|\\\\,)(?:[0-5]?\\\\d))?)*)\\\\s+(\\\\?|\\\\*|(?:[01]?\\\\d|2[0-3])(?:(?:-|\/|\\\\,)(?:[01]?\\\\d|2[0-3]))?(?:,(?:[01]?\\\\d|2[0-3])(?:(?:-|\/|\\\\,)(?:[01]?\\\\d|2[0-3]))?)*)\\\\s+(\\\\?|\\\\*|(?:0?[1-9]|[12]\\\\d|3[01])(?:(?:-|\/|\\\\,)(?:0?[1-9]|[12]\\\\d|3[01]))?(?:,(?:0?[1-9]|[12]\\\\d|3[01])(?:(?:-|\/|\\\\,)(?:0?[1-9]|[12]\\\\d|3[01]))?)*)\\\\s+(\\\\?|\\\\*|(?:[1-9]|1[012])(?:(?:-|\/|\\\\,)(?:[1-9]|1[012]))?(?:L|W)?(?:,(?:[1-9]|1[012])(?:(?:-|\/|\\\\,)(?:[1-9]|1[012]))?(?:L|W)?)*|\\\\?|\\\\*|(?:JAN|FEB|MAR|APR|MAY|JUN|JUL|AUG|SEP|OCT|NOV|DEC)(?:(?:-)(?:JAN|FEB|MAR|APR|MAY|JUN|JUL|AUG|SEP|OCT|NOV|DEC))?(?:,(?:JAN|FEB|MAR|APR|MAY|JUN|JUL|AUG|SEP|OCT|NOV|DEC)(?:(?:-)(?:JAN|FEB|MAR|APR|MAY|JUN|JUL|AUG|SEP|OCT|NOV|DEC))?)*)\\\\s+(\\\\?|\\\\*|(?:[0-6])(?:(?:-|\/|\\\\,|#)(?:[0-6]))?(?:L)?(?:,(?:[0-6])(?:(?:-|\/|\\\\,|#)(?:[0-6]))?(?:L)?)*|\\\\?|\\\\*|(?:MON|TUE|WED|THU|FRI|SAT|SUN)(?:(?:-)(?:MON|TUE|WED|THU|FRI|SAT|SUN))?(?:,(?:MON|TUE|WED|THU|FRI|SAT|SUN)(?:(?:-)(?:MON|TUE|WED|THU|FRI|SAT|SUN))?)*)(|\\\\s)+(\\\\?|\\\\*|(?:|\\\\d{4})(?:(?:-|\/|\\\\,)(?:|\\\\d{4}))?(?:,(?:|\\\\d{4})(?:(?:-|\/|\\\\,)(?:|\\\\d{4}))?)*))$/';
$str = '';
preg_match_all($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