$re = '/^([A-TV-Z|a-tv-z|\d])([\d])([A-TV-Z|a-tv-z|\d])(\.?)([A-TV-Z|a-tv-z|\d]{0,4})$/m';
$str = 'S62.0XX6
99.2
095.20
9S6
E27.09xx66
9090000
';
preg_match_all($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