$re = '/\(\w+\)(?:\[\d+\])?:(?:CID=[^;]*;)?(?<message>[^.]+\.)/m';
$str = '1. (s)[18014]:Recorded command information.
2. (l):User logged out.
3. (s)[18014]:CID=0x11aa2222;The user succeeded in logging out of XXX.';
preg_match_all($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