system.startup.chime: init

modules/module-list.nix

@@ -38,6 +38,7 @@
   ./system/nvram.nix
   ./system/patches.nix
   ./system/shells.nix
+  ./system/startup.nix
   ./system/version.nix
   ./time
   ./networking

modules/system/startup.nix

@@ -0,0 +1,31 @@
+{ config, lib, pkgs, ... }:
+
+let
+  cfg = config.system.startup;
+in
+
+{
+  meta.maintainers = [
+    lib.maintainers.samasaur or "samasaur"
+  ];
+
+  options = {
+    system.startup.chime = lib.mkOption {
+      type = with lib.types; nullOr bool;
+      default = null;
+      example = false;
+      description = lib.mdDoc ''
+        Whether to enable the startup chime.
+
+        By default, this option does not affect your system configuration in any way.
+        However, this means that after it has been set once, unsetting it will not
+        return to the old behavior. It will allow the setting to be controlled in
+        System Settings, though.
+      '';
+    };
+  };
+
+  config = {
+    system.nvram.variables."StartupMute" = lib.mkIf (cfg.chime != null) (if cfg.chime then "%00" else "%01");
+  };
+}