Originally started with: nix-starter-configs by Misterio77
Highly recommend that repository as a starting point even if it's a bit outdated.

Basic Usage

Switching to a Host

To switch to a host configuration (e.g., "atom"):

sudo nixos-rebuild switch --flake .#atom
# or with nh, add -u to update flake inputs
nh os switch -a -H atom .

This will apply the NixOS configuration defined for the "atom" host.

Switching Home Configuration

To switch home manager configuration for the user "matt":

home-manager switch --flake .#matt@atom
# or with nh, add -u to update flake inputs
nh home switch -a -c matt@atom .

---

Testing Configuration

To verify any flake changes without applying them:

nix flake check

To test a configuration without switching to it:

nixos-rebuild test --flake .#atom
# or with nh
nh os test -a -H atom .

Building Configuration

To build a configuration without applying it (will be applied on next boot):

nixos-rebuild build --flake .#atom
# or with nh
nh os build -a -H atom .

Or to build vm for testing:

nixos-rebuild build-vm --flake .#atom

then run:

QEMU_OPTS="-smp 4 -m 4096 -vga virtio" ./result/bin/run-*-vm

(QEMU_OPTS are for more resources)

---

Updating the Flake

Update Everything

To update all inputs in the flake:

nix flake update

Update Specific Input

To update a specific input (e.g., nixpkgs):

nix flake update nixpkgs

For another example, to update the zed-editor input:

nix flake update zed-editor

Modifying Configuration

Adding a New Host

1. Create a new directory under hosts/ for your host (e.g., hosts/newhost/)
2. Create a default.nix file in that directory with your host configuration
3. Generate a hardware configuration with nixos-generate-config and place it in the host directory
4. Add the host to the nixosConfigurations attribute in flake.nix:

nixosConfigurations = {
  atom = nixpkgs.lib.nixosSystem { ... };

  newhost = nixpkgs.lib.nixosSystem {
    specialArgs = { inherit inputs outputs; };
    modules = [
      ./hosts/newhost
    ];
  };
};

homeConfigurations = {
  "matt@atom" = home-manager.lib.homeManagerConfiguration { ... };

  "newuser@newhost" = home-manager.lib.homeManagerConfiguration {
    pkgs = nixpkgs.legacyPackages.x86_64-linux;
    extraSpecialArgs = {inherit inputs outputs;};
    modules = [
      ./home/newuser/newhost.nix
    ];
  };
};

Adding a New User Configuration

1. Create a new directory under home/ for your user if it doesn't exist
2. Create a configuration file for your user and host (e.g., home/newuser/newhost.nix)
3. Import the necessary modules and configure your home environment
4. Make sure to reference your home configuration in the host's entry in flake.nix

Modifying Existing Configuration

• System-wide settings: Edit the relevant files in the hosts/ directory
• User-specific settings: Edit the relevant files in the home/ directory
• Common modules: Edit or add files in the modules/ directory

Working with Programs

1. Add the relevant file in home/<user>/programs/
2. For adding a new program, create a new file and import it in home/<user>/programs/default.nix

Structure

nixos-flake/
├── flake.nix            # Main flake configuration
├── hosts/               # Host-specific configurations
│   ├── atom/            # Configuration for 'atom' host
│   └── common/          # Common configurations shared across hosts
├── home/                # Home-manager configurations
│   └── matt/            # Configuration for user 'matt'
│       ├── atom.nix
│       ├── desktop/     # Desktop-specific configurations (i3, rofi, etc.)
│       └── programs/    # Program-specific configurations
│       └── scripts/     # Scripts for user-specific tasks
└── modules/             # Custom modules
    └── home-manager/    # Home-manager modules

Formatting

You can format the Nix code with:

alejandra .

This uses the formatter configured in flake.nix.

Notes

• This configuration uses the unstable channel of NixOS
• Several custom modules are provided for home-manager