docs: public static String convertToFileSystemChar(String name) {
          String erg = "";
          Matcher m = Pattern.compile("[a-z0-9 _#&@\\[\\(\\)\\]\\-\\.]", Pattern.CASE_INSENSITIVE).matcher(name);
          while (m.find()) {
              erg += name.substring(m.start(), m.end());
          }
          if (erg.length() > 200) {
              erg = erg.substring(0, 200);
              System.out.println("cut filename: " + erg);
          }
          return erg;
      }