$re = '/^(?<SyslogPri><\d+>)(?<SyslogDate>[A-Z][a-z]+\s+\d+\s\d+:\d+:\d+)\s(?<SyslogHost>.*)\s(?<process>.*):\s(?<SyslogMessage>.*)$/';
$str = '<165>Dec 16 10:29:59 192.168.99.100 httpd[10583]: site1.example.org 10.4.5.6 - - [16/Dec/2014:10:29:59 -0800] "GET /rest/somepath/12345" HTTP/1.1" 200 105066 "-" "-"
';
preg_match($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