$re = '/\[([^:\]]+):\s+([^\]]+)\]/m';
$str = '2019-03-01T09:42:01 [status] [Thread: 5=/blah/blah] [Method: GET] [URI: /blah/blah] [Protocol: HTTP/1.1] [IP: 1.2.3.4] [Port: 54809] [Referer: https://referrer] [..] ... [..] text string here';
preg_match_all($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