$re = '/^\d{10}-\d{3}$/m';
$str = '989891832213213
987-12-1234
12-2343244
123123--123
1234567890-123
1234476895-120';
preg_match_all($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