$re = '/\d{11}\b/m';
$str = '00000000000 00000000001 00000000002 00000000003 00000000010 00000000011 00000000012 00000000014 00000000020 00000000021 00000000022 00000000024 00000000030 00000000031 00000000032 00000000034 00000000100 00000000101 00000000110 00000000111 00000000120 00000000121';
preg_match_all($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