$re = '/.*src\/(([^\/]*)(\/)?)|(\/)([^\/]*)/m';
$str = '/dev/project/src/MVC/Models/Access/Auth
/home/user/dev/project/src/MVC/Models/Access/Auth
/any_other_folder/src/MVC/Models/Access/Auth';
$subst = "$2\\$5";
$result = preg_replace($re, $subst, $str);
echo "The result of the substitution is ".$result;
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