$re = '/^((?!.*email).)*thank(\-|\_|)you.*/i';
$str = 'http://www.safesteptub.com/thank-you
http://www.safesteptub.com/email/thank-you/
NOTE:
Newlines are excluded as well. Please make sure the string you want to test is at the top of the list.
';
preg_match_all($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