$re = '/(?:[A-Z0-9]{8} ){7}[A-Z0-9]{8}/m';
$str = '1N2HY4C9 4JVNFYL8 4NCYTI84 12345678 QWERTYUI ASDFGHJK ZXCVBNMH QAZXSWED
PPOIUYTR 09876543 THNMJUIK MNBVCXZA 12345678 WDFGTYHJ TGBNHYTR QWERDDE3';
preg_match_all($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