anchor.diff:      inherit (cfg) revision;
       inherit pkgs options;
     };
  +
  +  entry = "${manual.manual}/share/doc/nixos/manual.html";
  +
  +  help = pkgs.writeScriptBin "nixos-help"
  +    ''
  +      #! ${pkgs.stdenv.shell} -e
  +      if ! ''${BROWSER:-w3m} ${entry}; then
  +        echo "$0: unable to start a web browser; please set \$BROWSER or install ‘w3m’"
  +        exit 1
  +      fi
  +    '';
   
   in
   
  
positive.code:         { description = "NixOS Manual";
            wantedBy = [ "multi-user.target" ];
            serviceConfig =
              { ExecStart = "${cfg.browser} ${manual.manual}/share/doc/nixos/manual.html";
                StandardInput = "tty";
                StandardOutput = "tty";
                TTYPath = "/dev/tty${cfg.ttyNumber}";
  
negative.code: 
      system.build.manual = manual;
  
      environment.systemPackages = [ manual.manpages help ];
  
      boot.extraTTYs = mkIf cfg.showManual ["tty${cfg.ttyNumber}"];
  
  