$re = '/(CAN|NUL|E(?:TX|NQ|SC)|S(?:OH|UB))(?:(?!\1).)*/s';
$str = '3NUL<123>lkjasdf lfdl;kja (432) adsfa sd 4ETX<342> sdfasdf asfds asdfa4(1 234)
4ETX<345> asdfasdf
NULSOH<342> sadfasd fasasdf asd 4ETX<345> asdfasdf ';
preg_match_all($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