$re = '/(is)..\d\d(-)\d\d\s(ifsd\[)\d\d\d\d\](:)\s(Changing logical)\s(drive)\s\d\d\s(from \w\w to \w\w\w\w\W)/';
$str = '2018-04-17T19:07:35-05:00 iswb01-12 ifsd[4189]: Changing logical drive 16 from OK to GONE.';
preg_match_all($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