Situatie

NixOS is a Linux distribution built around the Nix package manager, where the entire operating system is described as code. Instead of manually installing software and editing configuration files, you define your desired system state in configuration files.

Advantages include:

• Fully reproducible systems
• Atomic upgrades and rollbacks
• Declarative package management
• Reliable dependency isolation
• Easy migration between machines
• Excellent development environments

Part 1 – Preparation

Requirements

• 8 GB RAM minimum (16 GB recommended)
• 30+ GB storage
• USB flash drive (4 GB or larger)
• Internet connection
• UEFI firmware (recommended)

Download the latest NixOS ISO and verify its checksum before writing it to a USB drive.

1. Boot from the installation USB.
2. Select the graphical installer or minimal installer.
3. Open a terminal.

Become root if necessary:

sudo -i

Confirm networking:

ping nixos.org

List disks:

lsblk

Example:

nvme0n1
├─nvme0n1p1
├─nvme0n1p2

Assume:

Disk:
/dev/nvme0n1

Using GPT:

parted /dev/nvme0n1 -- mklabel gpt

EFI partition:

parted /dev/nvme0n1 -- mkpart ESP fat32 1MiB 512MiB
parted /dev/nvme0n1 -- set 1 esp on

Root:

parted /dev/nvme0n1 -- mkpart primary 512MiB 100%

Format EFI:

mkfs.fat -F32 /dev/nvme0n1p1

Format root:

mkfs.ext4 /dev/nvme0n1p2

mount /dev/nvme0n1p2 /mnt

mkdir -p /mnt/boot

mount /dev/nvme0n1p1 /mnt/boot

nixos-generate-config --root /mnt

Files created:

/mnt/etc/nixos/configuration.nix

/mnt/etc/nixos/hardware-configuration.nix

Edit:

nano /mnt/etc/nixos/configuration.nix

Example:

{ config, pkgs, ... }:

{
  imports = [
    ./hardware-configuration.nix
  ];

  boot.loader.systemd-boot.enable = true;

  boot.loader.efi.canTouchEfiVariables = true;

  networking.hostName = "desktop";

  time.timeZone = "Europe/Bucharest";

  i18n.defaultLocale = "en_US.UTF-8";

  services.xserver.enable = true;

  services.displayManager.gdm.enable = true;

  services.desktopManager.gnome.enable = true;

  users.users.alex = {
    isNormalUser = true;
    extraGroups = [ "wheel" "networkmanager" ];
  };

  networking.networkmanager.enable = true;

  environment.systemPackages = with pkgs; [
    git
    vim
    wget
    curl
  ];

  system.stateVersion = "26.05";
}

nixos-install

Set root password.

Reboot:

reboot

Remove the USB.

Edit:

/etc/nixos/configuration.nix

Add:

nix.settings.experimental-features = [
  "nix-command"
  "flakes"
];

Rebuild:

sudo nixos-rebuild switch

Directory:

/etc/nixos

Create:

flake.nix

Example:

{
  description = "Desktop";

  inputs = {
    nixpkgs.url = "github:NixOS/nixpkgs/nixos-unstable";
  };

  outputs = { self, nixpkgs }:

  {
    nixosConfigurations.desktop =
      nixpkgs.lib.nixosSystem {
        system = "x86_64-linux";

        modules = [
          ./configuration.nix
        ];
      };
  };
}

Rebuild:

sudo nixos-rebuild switch --flake /etc/nixos#desktop

Temporarily:

nix shell nixpkgs#ripgrep

Run once:

nix run nixpkgs#hello

Permanent:

environment.systemPackages = with pkgs; [
  firefox
  git
  neovim
  ripgrep
  fd
  htop
  tmux
];

Install Home Manager as a flake input.

Benefits:

• User configuration as code
• Dotfile management
• Reproducible shell configuration
• Declarative editor setup
• Version-controlled user environment

Example modules:

• Git
• Zsh
• Bash
• Neovim
• Alacritty
• Kitty
• VS Code
• SSH
• GPG
• Starship

Delete old generations:

sudo nix-collect-garbage -d

Automatic cleanup:

nix.gc = {
  automatic = true;
  dates = "weekly";
  options = "--delete-older-than 30d";
};

List generations:

sudo nix profile history

Rollback:

sudo nixos-rebuild switch --rollback

You can also select previous system generations directly from the bootloader if a rebuild prevents the system from booting.

Update flake inputs:

nix flake update

Apply:

sudo nixos-rebuild switch --flake /etc/nixos

SSH:

services.openssh.enable = true;

Docker:

virtualisation.docker.enable = true;

PipeWire:

services.pipewire = {
  enable = true;
  pulse.enable = true;
};

Printing:

services.printing.enable = true;

Bluetooth:

hardware.bluetooth.enable = true;

Example development shell:

{
  description = "Example dev shell";

  inputs.nixpkgs.url = "github:NixOS/nixpkgs/nixos-unstable";

  outputs = { self, nixpkgs }:
  let
    pkgs = import nixpkgs {
      system = "x86_64-linux";
    };
  in {
    devShells.x86_64-linux.default =
      pkgs.mkShell {
        packages = with pkgs; [
          git
          gcc
          cmake
          python3
        ];
      };
}

Enter:

nix develop

nixos/

├── flake.nix
├── flake.lock
├── hosts/
│   └── desktop
├── modules/
│   ├── networking.nix
│   ├── users.nix
│   ├── desktop.nix
│   ├── fonts.nix
│   └── services.nix
├── home/
│   ├── git.nix
│   ├── shell.nix
│   ├── nvim.nix
│   └── zsh.nix

Keeping configuration modular makes it easier to reuse components across multiple systems and simplifies maintenance.

Configuration errors

Validate before switching:

sudo nixos-rebuild test

Boot issues

• Confirm the EFI partition is mounted at /boot.
• Verify boot.loader.systemd-boot.enable = true;.
• Ensure UEFI mode is enabled in firmware.

Network problems

Verify NetworkManager:

systemctl status NetworkManager

Flake errors

Refresh lock file:

nix flake update

Or remove flake.lock and regenerate it if dependency resolution becomes inconsistent.

Solutie

Tip solutie

Permanent