anchor.diff:        # 1) Only the "transmission" user and group have access to torrents.
         # 2) Optionally update/force specific fields into the configuration file.
         serviceConfig.ExecStartPre = ''
  -          ${pkgs.stdenv.shell} -c "chmod 770 ${homeDir} && mkdir -p ${settingsDir} ${downloadDir} ${incompleteDir} && rm -f ${settingsDir}/settings.json && cp -f ${settingsFile} ${settingsDir}/settings.json"
  +          ${pkgs.stdenv.shell} -c "mkdir -p ${homeDir} ${settingsDir} ${fullSettings.download-dir} ${fullSettings.incomplete-dir} && chmod 770 ${homeDir} ${settingsDir} ${fullSettings.download-dir} ${fullSettings.incomplete-dir} && rm -f ${settingsDir}/settings.json && cp -f ${settingsFile} ${settingsDir}/settings.json"
         '';
         serviceConfig.ExecStart = "${pkgs.transmission}/bin/transmission-daemon -f --port ${toString config.services.transmission.port}";
         serviceConfig.ExecReload = "${pkgs.coreutils}/bin/kill -HUP $MAINPID";
  
positive.code:     else toString ''"${x}"'';
  
    # for users in group "transmission" to have access to torrents
    fullSettings = cfg.settings // { umask = 2; };
  in
  {
    options = {
  
negative.code:           Transmission daemon can be controlled via the RPC interface using
            transmission-remote or the WebUI (http://localhost:9091/ by default).
  
            Torrents are downloaded to ${downloadDir} by default and are
            accessible to users in the "transmission" group.
          '';
        };
  