$re = '/((?:(?:ht|f)tps?:\/\/|www)[^\s,?!]+(?!.*<\/a>))/m';
$str = 'http://www.example.com
http://www.example.com/test
http://example.com/test
www.example.com/test
https://www.example.com
<a href="http://www.example.com">http://www.example.com </a>
<a href="http://www.example.com/test">http://www.example.com/test </a>
<a href="http://example.com/test">http://example.com/test </a>
<a href="www.example.com/test">www.example.com/test </a>
<a href="www.example.com/test"><img src="www.example.com/test,jpg" /></a>';
preg_match_all($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