{ config, pkgs, ... }: with pkgs.lib; { options = { time = { timeZone = mkOption { default = "CET"; type = with types; uniq string; example = "America/New_York"; description = "The time zone used when displaying times and dates."; }; hardwareClockInLocalTime = mkOption { default = false; description = "If set, keep the hardware clock in local time instead of UTC."; }; }; }; config = { environment.shellInit = '' export TZ=${config.time.timeZone} export TZDIR=${pkgs.tzdata}/share/zoneinfo ''; environment.etc = singleton { source = "${pkgs.tzdata}/share/zoneinfo/${config.time.timeZone}"; target = "localtime"; }; }; }