NixOS Configurations

This repository is a flake-based NixOS configuration for my daily machines. It is also meant to be a readable example of how to grow a personal NixOS setup from one machine into a reusable multi-host configuration.

Quick Start

Clone the repository and make /etc/nixos point to it:

git clone https://github.com/RandomLemon/nixos.git
sudo rm -rf /etc/nixos
sudo ln -s "$PWD/nixos" /etc/nixos

Rebuild one of the configured hosts:

sudo nixos-rebuild switch --flake /etc/nixos#tx
sudo nixos-rebuild switch --flake /etc/nixos#thinkpad
sudo nixos-rebuild switch --flake /etc/nixos#msr1

There is also a shell alias named update, defined in home-manager/zsh.nix, which runs:

sudo nixos-rebuild switch

When using flakes directly, prefer the explicit --flake /etc/nixos#<host> form so it is always clear which machine is being rebuilt.

Learning Path

If you are learning NixOS from this repository, read it in this order:

1. flake.nix to understand inputs, outputs, and host creation.
2. One host file, such as hosts/fa401wv/default.nix, to see how a machine is assembled from modules.
3. modules/software/system/main.nix to learn the base system policy.
4. modules/hardware/default.nix and its imported files to learn reusable hardware defaults.
5. hosts/fa401wv/home.nix and home-manager/ to see user-level configuration.
6. home-manager/desktop/niri/ to study a complete Wayland desktop config.

The important lesson is separation of responsibility:

• flake.nix decides which machines exist.
• hosts/ decides what each machine imports.
• modules/ contains reusable operating system building blocks.
• home-manager/ contains user applications and dotfiles.
• Hardware-generated files stay close to the machine that needs them.

That structure keeps daily use convenient while making the configuration easier to explain, copy, and modify.

Repository Layout

.
|-- flake.nix
|-- flake.lock
|-- hosts/
|   |-- fa401wv/
|   |-- thinkpad/
|   `-- msr1/
|-- modules/
|   |-- hardware/
|   `-- software/
`-- home-manager/
    |-- core.nix
    |-- applications.nix
    |-- zsh.nix
    |-- code.nix
    `-- desktop/

The main idea is simple:

flake.nix
  -> hosts/<machine>/default.nix
    -> shared NixOS modules in modules/
    -> optional Home Manager profile in hosts/<machine>/home.nix
      -> shared user modules in home-manager/

flake.nix

flake.nix is the top-level entry point. It defines:

• Inputs such as nixpkgs, home-manager, nix-alien, and a CachyOS kernel overlay.
• Binary cache settings, including several mirrors.
• A small mkHost helper that creates each nixosSystem.
• The user name shared by the hosts: int16. Change it as you wish.
• Home Manager integration.

This is the first file to read if you want to understand how the whole project is assembled.

hosts/

Host files decide which reusable modules are active on a specific machine.

The flake currently exposes these NixOS configurations:

Flake name	Host directory	System	Home Manager	Purpose
tx	hosts/fa401wv	x86_64-linux	Yes	For ASUS FA401WV 2024, with a Ryzen HX 370 and a RTX 4060
thinkpad	hosts/thinkpad	x86_64-linux	Yes	Legacy ThinkPad configuration with legacy GRUB boot, based on T430

Each host usually contains:

hosts/<machine>/
  default.nix                 # NixOS system entry point
  home.nix                    # Home Manager entry point, when used
  hardware-configuration.nix  # generated by nixos-generate-config
  hardware/                   # optional machine-specific hardware modules

Treat hardware-configuration.nix as generated hardware state. For a new machine, regenerate it with nixos-generate-config instead of copying another host's file blindly.

For example, hosts/fa401wv/default.nix imports:

• Generated hardware configuration.
• Hardware-specific ASUS laptop modules.
• Shared hardware defaults from modules/hardware.
• Shared system defaults from modules/software/system/main.nix.
• Development tools such as direnv and distrobox.
• Gaming modules such as Steam and Prism Launcher.
• The greetd login manager and the Niri desktop session.

The tx flake output uses the hosts/fa401wv directory. This is useful to remember when reading the tree: the flake name is the rebuild target, while the directory name describes the hardware model.

hosts/thinkpad/default.nix uses the same shared base, but overrides bootloader settings to use legacy GRUB on /dev/sda.

hosts/msr1/default.nix is more standalone because it targets ARM64 hardware and builds a custom kernel.

modules/

modules/ contains reusable NixOS modules. These affect the whole operating system.

modules/hardware/
  default.nix     # imports the common hardware modules
  main.nix        # bootloader, kernel, firmware, filesystem helpers
  network.nix     # NetworkManager, timezone, base hostname
  input.nix       # locale, fonts, fcitx5, keyboard settings
  bluetooth.nix   # Bluetooth and Blueman
  pipewire.nix    # PipeWire audio

modules/software/
  system/         # base OS policy and common CLI tools
  desktop/        # greetd, niri, hyprland, KDE, LXQt
  develop/        # direnv, distrobox, docker, mysql
  game/           # Steam, Minecraft / Prism Launcher, Waydroid
  3rd/            # third-party packages

The most important shared system module is modules/software/system/main.nix. It enables unfree packages, creates the normal user, configures Git, enables flakes, configures garbage collection, sets the default shell to Zsh, installs common tools, and enables services such as udisks2, Polkit, and GNOME keyring integration.

home-manager/

home-manager/ contains user-level configuration. These modules are imported from each host's home.nix.

Important files:

• core.nix sets the base Home Manager state, user services, dconf values, and desktop preferences.
• applications.nix installs daily graphical applications and declares XDG default applications.
• zsh.nix configures Zsh, Oh My Zsh, shell plugins, and aliases.
• code.nix installs and configures VS Code / Cursor.
• desktop/niri/ contains the active Niri desktop configuration.
• desktop/hyprland/ contains an alternative Hyprland desktop setup.

Home Manager is not used as a standalone command here. It is wired into the NixOS rebuild through flake.nix.

Desktop Stack

The current desktop stack is Wayland-first:

greetd / tuigreet
  -> niri-session
    -> Niri compositor
    -> Waybar
    -> fuzzel, mako, swaylock, swayidle, xwayland-satellite, wl-clipboard

System-level desktop pieces live in modules/software/desktop/:

• greetd.nix configures the login manager.
• niri.nix enables Niri and supporting desktop services.
• hyprland.nix, kde.nix, and lxqt.nix are alternative desktop modules.

User-level desktop configuration lives under home-manager/desktop/:

• desktop/niri/default.nix installs the Niri user tools.
• desktop/niri/*.kdl split the Niri configuration into focused files for input, outputs, keybindings, layout, startup commands, and window rules.
• desktop/waybar/ contains the bar configuration.
• desktop/hyprland/ keeps the older Hyprland setup available as a reference or alternate session.

To switch between Niri and Hyprland, change both layers:

1. In the host system file, switch the imported desktop module, for example in hosts/fa401wv/default.nix.
2. In the host Home Manager file, switch the imported user desktop module, for example in hosts/fa401wv/home.nix.

Keeping the system session and the Home Manager desktop files in sync avoids a login session that starts without the matching user tools.

Hardware Notes

ASUS FA401WV / tx

This is the most complete daily-driver configuration.

Notable pieces:

• hosts/fa401wv/hardware/default.nix contains machine-specific tuning such as power management, battery settings, fstrim, and sensors.
• hosts/fa401wv/hardware/nvidia.nix configures AMD + NVIDIA PRIME offload and GPU-related environment.
• hosts/fa401wv/hardware/asus.nix enables ASUS laptop services.
• hosts/fa401wv/hardware/custom-dsdt.nix is a custom DSDT experiment for ACPI fixes.
• The flake applies the CachyOS LTO Zen4 kernel overlay for this host.
• The host also enables nix-ld, nix-alien, and wemeet.

ThinkPad

The ThinkPad host uses the shared desktop base but has different boot settings: systemd-boot is disabled and GRUB is installed to /dev/sda.

MSR1

The MSR1 host targets aarch64-linux and keeps most configuration inside its own host file because it uses a custom CIX P1 kernel setup. Currently it doesn't work...

Daily Maintenance

Common commands:

# Rebuild the current machine explicitly
update
# update is the alias of `sudo nixos-rebuild switch`

# Update flake inputs
nix flake update /etc/nixos

# Inspect what changed after an update
git diff flake.lock

# Build without switching, useful before risky changes
sudo nixos-rebuild build --flake /etc/nixos#tx

Garbage collection and store optimisation are configured in modules/software/system/main.nix:

• Automatic GC runs weekly.
• Generations older than 14 days are deleted.
• Nix store optimisation is enabled automatically.

Adding a New Host

To use this repository as a template for a new machine:

1. Create a new host directory:

   mkdir -p hosts/my-machine

2. Generate hardware configuration on the target machine:

   sudo nixos-generate-config --dir /etc/nixos/hosts/my-machine

3. Create hosts/my-machine/default.nix and import the shared modules you need:

   { config, pkgs, lib, username, ... }:
   {
     imports = [
       ./hardware-configuration.nix
       ../../modules/hardware
       ../../modules/software/system/main.nix
       ../../modules/software/develop/direnv.nix
       ../../modules/software/desktop/greetd.nix
       ../../modules/software/desktop/niri.nix
     ];
   
     networking.hostName = "my-machine";
   }

4. Optionally create hosts/my-machine/home.nix:

   { pkgs, lib, username, ... }:
   {
     imports = [
       ../../home-manager/core.nix
       ../../home-manager/applications.nix
       ../../home-manager/zsh.nix
       ../../home-manager/code.nix
       ../../home-manager/desktop/niri
     ];
   }

5. Add the host to nixosConfigurations in flake.nix:

   my-machine = mkHost {
     system = "x86_64-linux";
     hostModule = ./hosts/my-machine;
     homeModule = ./hosts/my-machine/home.nix;
   };

6. Build or switch:

   sudo nixos-rebuild build --flake /etc/nixos#my-machine
   sudo nixos-rebuild switch --flake /etc/nixos#my-machine