{ config, pkgs, ... }: { # creates the file /etc/current-system-packages which then contains all installed packages and versions environment.etc."current-system-packages".text = let packages = builtins.map (p: "${p.name}") config.environment.systemPackages; sortedUnique = builtins.sort builtins.lessThan (pkgs.lib.lists.unique packages); formatted = builtins.concatStringsSep "\n" sortedUnique; in formatted; }