$re = '/^[\w,\s-]+\.[A-Za-z]{3}$/m';
$str = 'resource.zip
resource.jpg
resource.ext
resource
resource.
resource.d
resource.long
resource.mov
resour#ce.png
// You can show origina post on albertcolom.com/blog';
preg_match_all($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