{
  # manipulate the global /etc/zshenv for PATH, etc.
  programs.zsh.enable = true;

  # Used for backwards compatibility, please read the changelog before changing.
  # $ darwin-rebuild changelog
  system.stateVersion = 4;

  security.pam.enableSudoTouchIdAuth = true;
  system.defaults.alf.stealthenabled = 1;

  # Auto upgrade nix package and the daemon service.
  services.nix-daemon.enable = true;
}