$re = '/^(\S*).*\[(.*)\]\s"(\S*)\s(\S*)\s([^"]*)"\s(\S*)\s(\S*)\s"([^"]*)"\s"([^"]*)"$/';
$str = '52.20.244.144 - - [24/Aug/2015:06:50:57 -0400] "GET /hol/contact.action?subject=Question+about+Junior+Essay+Contest&title=Susan+Harlow&webUserKeys=13900 HTTP/1.1" 200 5921 "http://holsteinusa.com/news/press_release2015.html" "Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/535.24 (KHTML, like Gecko) Chrome/19.0.1055.1 Safari/535.24"';
preg_match($re, $str, $matches, PREG_OFFSET_CAPTURE, 0);
// Print the entire match result
var_dump($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