Example NixOS config

configuration.nix

{ config, pkgs, ... }:

{
  imports = [ <nixpkgs/nixos/modules/installer/virtualbox-demo.nix> ];

  networking.firewall.enable = false;

  # Enables the SSH Daemon
  services.openssh.enable = true;
  services.openssh.forwardX11 = true;  # Adds X11Forwarding yes to /etc/ssh/sshd_config

  # List of packages installed in system profile.
  environment.systemPackages = with pkgs; [
    vim xorg.xhost
  ];

  # Enables TCP for the X server
  #services.xserver.enableTCP = true;
  #services.xserver.displayManager.sddm.extraConfig = ''
  #  [X11]
  #  ServerArguments=-listen tcp
  #'';

  # Let demo build as a trusted user.
  #nix.trustedUsers = [ "demo" ];

  # Mount a VirtualBox shared folder.
  # This is configurable in the VirtualBox menu at
  # Machine / Settings / Shared Folders.
  #fileSystems."/vboxsf" = {
  #  fsType = "vboxsf";
  #  device = "nameofdevicetomount";
  #  options = [ "rw" ];
  #};

  # By default, the NixOS VirtualBox demo image includes SDDM and Plasma.
  # If you prefer another desktop manager or display manager, you may want
  # to disable the default.
  #services.xserver.desktopManager.plasma5.enable = lib.mkForce false;
  #services.xserver.displayManager.sddm.enable = lib.mkForce false;

  # Enable GDM/GNOME by uncommenting above two lines and two lines below.
  #services.xserver.displayManager.gdm.enable = true;
  #services.xserver.desktopManager.gnome3.enable = true;

  # Set your time zone.
  #time.timeZone = "Europe/Amsterdam";
}