$re = '/^ *(\d *){6,10}$/m';
$str = '1 2345
123 45
12345
123 45678912
1 23456
123 456
123456 789 1
12 345 678 90';
preg_match_all($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