$re = '/([0-9]{2}\.[0-9]{2}\.[0-9]{4}\s[0-9]{2}:[0-9]{2}:[0-9]{2}).*?\n-{1,}\sFG\s+?4/m';
$str = '19.04.2016 01:59:18 ASDF
---- FG 3
--------------- ASDF
19.04.2016 01:59:21 ASDF
---- FG 4
--------------- ASDF
19.04.2016 01:59:22 ASDF
---- FG 4
--------------- ASDF';
preg_match($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