$re = '/(?P<req_ip>^[\d\.]+)\s+(?P<req_identity>.+?)\s+(?P<req_user>.+?)\s+(?P<req_date>.+?)\s+(?P<req_offset>.+?)\s+"(?P<req_method>.+?)\s+(?P<req_path>.+?)\s+(?P<req_protocoll>.+?)"\s+(?P<req_code>.+?)\s+(?P<req_size>.+?)\s+"(?P<req_referer>.+?)"\s+"(?P<req_device>.+?)"/m';
$str = '165.72.104.6 - admin 12/May/2021:09:37:52 +0000 "GET /etc/clientlibs/website/global/public/img/loading.gif HTTP/1.1" 200 17585 "https://my.domain.com/etc/clientlibs/website/global/public/stylesheets/project-base.108cb261dae9b1ccd0121c7571bbd42f2fc6d0a78a9bffb03b16be08753a32ad.css" "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/90.0.4430.212 Safari/537.36"';
preg_match_all($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