{ config, lib, pkgs, ... }: with lib; let cfg = config.programs.light; in { options = { programs.light = { enable = mkOption { default = false; type = types.bool; description = '' Whether to install Light backlight control command and udev rules. ''; }; }; }; config = mkIf cfg.enable { environment.systemPackages = [ pkgs.light ]; services.udev.packages = [ pkgs.light ]; }; }