$re = '/^[A-Za-z,.\'-]{2,} +[A-Za-z,.\'-]{2,}$/m';
$str = 'firstname
Lastname
F lastname
firstname l
Firstname Lastname
f-name lastname
someguy en\'try
Patrick O\'Brian
web dev@
\'f names
Mr. Bean
.hidden file';
preg_match_all($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