$re = '/[a-zA-Z]{3,4}[0-9]{2}[0-1]{1}[0-9]{1}[0-3]{1}[0-9]{1}[a-zA-Z0-9]{3}/';
$str = 'UGU250907MH5
UGU001939333
HHHH250907MH5
BBBBB20907MH5';
preg_match_all($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