Add battery command

modules/scripts/battery.nix

@@ -0,0 +1,17 @@
+{
+  flake.modules.homeManager.gui =
+    { pkgs, ... }:
+    {
+      home.packages = [
+        (pkgs.writeShellApplication {
+          name = "battery";
+
+          runtimeInputs = with pkgs; [ upower ];
+
+          text = ''
+            upower -i /org/freedesktop/UPower/devices/battery_BAT1 | grep -E 'state|to full|percentage'
+          '';
+        })
+      ];
+    };
+}