$re = '/(https?:\/\/(www.|de.)?linkedin.com\/(mwlite\/|m\/)?in\/([a-zA-Z0-9À-ž_.-]+)\/?)/m';
$str = 'https://de.linkedin.com/in/andré-test-9dfdr47a16a
https://www.linkedin.com/in/lenatest/
https://de.linkedin.com/in/test-jäcke-dff0746
https://de.linkedin.com/in/irenetest
https://www.linkedin.com/in/markus-test-7dfdfc38/?originalSubdomain=de
https://www.linkedin.com/in/test-görs-2fdf562a/
https://www.linkedin.com/in/test-müller-82dfdfd0143/
https://www.linkedin.com/in/marie-test-grübler-dfdfdsf0/
https://www.linkedin.com/in/özgür-test-dfdfdf080/';
preg_match_all($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