$re = '/rr\d---sn-[a-z0-9]{8}-\w{4}\.googlevideo\.com/m';
$str = 'rr9--- - -abcd.googlevideo.com
rr1---sn-8xgn5uxa-quhl.googlevideo.com
rr1---sn-8xgn5uxa-quhl.googlevideo.com
rr3---sn-8xgn5uxa-quhz.googlevideo.com
rr6---sn-8xgn5uxa-quhl.googlevideo.com';
preg_match_all($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