name: nixos description: Use when the user asks about NixOS, Nix language, flakes, nixpkgs, configuration.nix, nixos-rebuild, modules, options, overlays, derivations, mkDerivation, callPackage, home-manager, nix-darwin, devenv, packaging, cross-compilation, binary caches, garbage collection, NixOS containers, networking, firewall, systemd services, filesystems, LUKS, Wayland, X11, kernel, profiles, NixOS testing or VM tests, ISO images, Docker images, Raspberry Pi, Terraform, distributed builds, remote machines, pinning nixpkgs, rollback, generations, Nix Pills, or any topic related to configuring, packaging, deploying, or troubleshooting NixOS and the Nix ecosystem. version: 0.1.0

NixOS Documentation

Complete reference for NixOS and the Nix ecosystem, auto-generated from official repositories:

• nix.dev — tutorials, guides, best practices
• NixOS Manual — from NixOS/nixpkgs
• Nix Pills — progressive learning series
• Release Wiki — NixOS release process

The references/ directory contains full, unmodified documentation from those sources, updated daily.

Directives

• Base all answers on the official NixOS documentation in the reference files below.
• Use correct Nix language syntax (attribute sets, let-in, with, inherit, etc.).
• Distinguish between NixOS module options (services.nginx.enable = true;) and Nix language expressions (pkgs.mkDerivation { ... }).
• Show configuration examples using current NixOS syntax (configuration.nix or flake-based configs).
• When flakes are relevant, show both the classic (channels) and flakes approach if applicable.
• For packaging, prefer the callPackage pattern over raw import.

Reference Files

Identify the topic from the user's question, then read the matching reference file:

Getting Started

Nix Language & Concepts

NixOS Configuration

NixOS Administration

NixOS Development

Packaging & Build

Tutorials

Guides & Recipes

Release Process

Live Fetching

When reference files are insufficient, fetch the latest docs from raw GitHub:

nix.dev

https://raw.githubusercontent.com/NixOS/nix.dev/master/source/<path>.md

NixOS Manual (nixpkgs)

https://raw.githubusercontent.com/NixOS/nixpkgs/master/nixos/doc/manual/<section>/<file>.md

Nix Pills

https://raw.githubusercontent.com/NixOS/nix-pills/master/pills/<NN>-<slug>.md

Strategy

1. Identify the topic from the user's question.
2. Read the matching reference file from the tables above.
3. Answer with correct Nix syntax and configuration.nix / flake.nix examples.
4. If more detail is needed, fetch from the corresponding raw GitHub URL.
5. For beginners, recommend starting with references/first-steps.md or references/nix-pills.md.
6. For troubleshooting, check references/troubleshooting.md and references/faq.md first.
7. For NixOS system issues, check references/nixos-administration.md.

Quick Reference

Config file location

/etc/nixos/configuration.nix (classic) or flake.nix (flakes)

Rebuild system

sudo nixos-rebuild switch          # apply config
sudo nixos-rebuild test            # apply without adding to bootloader
sudo nixos-rebuild build           # build only
sudo nixos-rebuild boot            # apply on next boot

Nix shell (ad-hoc packages)

nix-shell -p python3 git vim       # classic
nix shell nixpkgs#python3 nixpkgs#git  # flakes

Nix develop (dev environment)

nix develop                        # from flake.nix devShell
nix-shell                          # from shell.nix

Search packages

nix search nixpkgs firefox
# or https://search.nixos.org/packages

Garbage collection

nix-collect-garbage -d             # delete all old generations
nix store gc                       # flakes equivalent
sudo nix-collect-garbage -d        # also clean system profiles

Flake basic structure

{
  inputs = {
    nixpkgs.url = "github:NixOS/nixpkgs/nixos-unstable";
  };
  outputs = { self, nixpkgs }: {
    nixosConfigurations.hostname = nixpkgs.lib.nixosSystem {
      system = "x86_64-linux";
      modules = [ ./configuration.nix ];
    };
  };
}

NixOS module syntax

{ config, pkgs, ... }:
{
  services.nginx.enable = true;
  environment.systemPackages = with pkgs; [ vim git firefox ];
  networking.firewall.allowedTCPPorts = [ 80 443 ];
  users.users.myuser = {
    isNormalUser = true;
    extraGroups = [ "wheel" "networkmanager" ];
  };
}