anchor.diff:    # List packages installed in system profile. To search, run:
     # $ nix search wget
     environment.systemPackages = with pkgs; [
  -    (python27Full.withPackages(ps: with ps; [ pydbus pygobject3 py3status pip requests tkinter virtualenv ]))
  -    (python36Full.withPackages(ps: with ps; [ pip requests tkinter virtualenv ]))
  +    (python27Full.withPackages(ps: with ps; [ pip requests tkinter virtualenv ]))
  +    (python36Full.withPackages(ps: with ps; [ i3ipc pydbus pygobject3 py3status pip requests tkinter virtualenv ]))
       arc-icon-theme
       arc-theme
  +    blueman
       compton
       curl
       dunst
       ffmpeg
       ffmpegthumbnailer
       firefox
  +    fzf
       gcc
       gitFull
       glxinfo
  
positive.code:     termite
      vim
      wget
      xdg-user-dirs
      xorg.xbacklight
      xorg.xdpyinfo
  
negative.code:   };
  
    # Enable TLP to reduce energy consumption.
    services.tlp = {
      enable = true;
      extraConfig = ''
        # Enable powersave governor
        CPU_SCALING_GOVERNOR_ON_AC=powersave
        CPU_SCALING_GOVERNOR_ON_BAT=powersave
      '';
    };
  
    # Trim SSD periodically.
    services.fstrim = {
  