$re = '/^https\:\/\/\S+?\.domain.ru$/m';
$str = 'https://login1.domain.ru
https://login2.domain.ru
https://login3.domain.ru
https://login4.domain.ru
https://login4.domain1.ru
https://123.domain.ru
https://login-5.domain.ru
https://login4.1domain.ru
http://login.domain.ru
https://domain.ru
https://login99.domain.ru';
preg_match_all($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