Full NixOS Guide: Everything You Need to Know in One Place! - Ampersand

1. Summary

This comprehensive guide provides an in-depth introduction to NixOS, a declarative Linux distribution built around the Nix package manager. The video aims to equip viewers with the foundational knowledge to understand, install, and begin configuring NixOS. It covers the core concepts of Nix, its declarative nature, the Nix language, and how to manage packages and system configurations. The guide also touches upon essential tools like Home Manager and Disko, and provides valuable resources for further learning.

2. Key Takeaways

* **Declarative System Configuration:** NixOS allows you to define your entire system configuration in code, ensuring reproducibility and reliability.

* **Nix Package Manager:** The foundation of NixOS, Nix offers a unique approach to package management, enabling atomic upgrades/rollbacks and isolated environments.

* **Nix Language:** A functional, lazy, and pure programming language used for defining packages and system configurations.

* **NixOS Configuration File (`configuration.nix`):** The central file where you define your system's settings, packages, services, and users.

* **Home Manager:** A tool for managing user-specific configurations declaratively, separate from the system configuration.

* **Disko:** A declarative disk partitioning and formatting tool that integrates well with NixOS.

* **Reproducibility and Rollbacks:** A major benefit of NixOS is its ability to reliably reproduce system states and easily roll back to previous configurations.

* **Nix Ecosystem:** A rich set of tools, guides, and communities exist to support NixOS users.

3. Detailed Notes

I. Introduction to NixOS and Nix

* **What is NixOS?**

* A Linux distribution.

* Built around the Nix package manager.

* Focuses on declarative system configuration.

* **What is Nix?**

* A powerful package manager.

* Enables atomic upgrades and rollbacks.

* Packages are stored in isolation, preventing dependency hell.

* Uses a unique store path (e.g., `/nix/store/...)` for each package.

* **Declarative Configuration:**

* Define the desired state of your system in configuration files.

* NixOS ensures the system matches that definition.

* Contrast with imperative configuration (executing commands sequentially).

II. The Nix Language

* **Functional, Lazy, Pure:**

* **Functional:** Emphasizes functions and immutability.

* **Lazy:** Evaluated only when needed.

* **Pure:** Given the same inputs, always produces the same output.

* **Syntax:**

* Basic data types: strings, integers, booleans, lists, sets (attribute sets).

* Functions are first-class citizens.

* Uses `let ... in ...` for variable bindings.

* Example:

```nix

let

myVar = "Hello";

in

myVar + " NixOS";

```

III. NixOS Installation and Configuration

* **Downloading NixOS:**

* Link: [https://nixos.org/download/](https://nixos.org/download/)

* **Installation Process:**

* Boot from the NixOS installation ISO.

* Partition disks (mention Disko here).

* Configure the system via `configuration.nix`.

* **`configuration.nix`:**

* The main configuration file (usually located at `/etc/nixos/configuration.nix`).

* Defines system-wide settings.

* **Key Sections:**

* `imports`: To include other Nix files.

* `networking`: Network configuration (hostname, interfaces).

* `time.timeZone`: Time zone setting.

* `i18n.defaultLocale`: Locale settings.

* `services`: Enables and configures system services (e.g., `services.xserver`, `services.sshd`).

* `users.users.<username>`: User accounts, groups, SSH keys.

* `environment.systemPackages`: Packages to install globally.

* `system.stateVersion`: Crucial for managing NixOS upgrades and compatibility.

* **Applying Changes:**

* `sudo nixos-rebuild switch`: Rebuilds the system configuration and switches to it.

* `sudo nixos-rebuild boot`: Rebuilds and adds the new configuration to the boot menu (for testing).

* `sudo nixos-rebuild test`: Builds the configuration and runs it in a temporary environment (for testing).

IV. Package Management with Nix

* **Nixpkgs:**

* The central repository of packages for Nix.

* Search: [https://search.nixos.org/packages](https://search.nixos.org/packages)

* **Installing Packages:**

* **System-wide:** Add to `environment.systemPackages` in `configuration.nix`.

* **Imperative (Temporary/Development):**

* `nix-env -iA nixpkgs.package_name` (Older, less recommended for reproducible builds)

* `nix build nixpkgs#package_name` (Creates a symlink in `./result`)

* `nix shell nixpkgs#package_name` (Enters a shell with the package available)

* **Nix Channels:**

* Used to pin specific versions of Nixpkgs.

* `nix-channel --list`: Lists current channels.

* `nix-channel --update`: Updates channels.

V. Home Manager

* **Purpose:** Manage user-specific configurations declaratively, separate from `configuration.nix`.

* **Benefits:**

* Reproducible user environments.

* Easier to share dotfiles and user configurations.

* **Installation (Example):**

* Add Home Manager channel:

```bash

$ nix-channel --add https://github.com/nix-community/home-manager/archive/master.tar.gz home-manager

$ nix-channel --update

```

* Import into `configuration.nix`:

```nix

imports = [

# ... other imports

./home-manager.nix # Assuming you create this file

];

```

* Create `home-manager.nix` (or similar) and configure user packages, dotfiles, etc.

* **Option Search:** [https://home-manager-options.extranix.com/](https://home-manager-options.extranix.com/)

VI. Disko - Declarative Disk Partitioning

* **Purpose:** Define disk partitioning and formatting in a declarative Nix configuration.

* **Integration:** Used during NixOS installation to set up disks.

* **Templates:** [https://github.com/nix-community/disko](https://github.com/nix-community/disko)

* **Example Usage:** Often imported into `configuration.nix` for disk setup.

VII. Learning Resources

* **My Config:** [https://github.com/Andrey0189/nixos-config](https://github.com/Andrey0189/nixos-config) (Example of a NixOS configuration)

* **NixOS Manual:** [https://nixos.org/manual/nixos/stable/](https://nixos.org/manual/nixos/stable/) (Official documentation for NixOS)

* **Nix Reference Manual:** [https://nixos.org/manual/nix/stable/](https://nixos.org/manual/nix/stable/) (Official documentation for the Nix package manager)

* **Nix Pills:** [https://nixos.org/guides/nix-pills/](https://nixos.org/guides/nix-pills/) (In-depth guides on Nix concepts)

* Specifically, Nix Pills - 06: [https://nixos.org/guides/nix-pills/06-how-nix-works.html](https://nixos.org/guides/nix-pills/06-how-nix-works.html) (As linked in the description)

* **Zero to Nix:** [https://zero-to-nix.com/](https://zero-to-nix.com/) (A comprehensive guide for learning Nix)

* **PhD Thesis:** [https://edolstra.github.io/pubs/phd-thesis.pdf](https://edolstra.github.io/pubs/phd-thesis.pdf) (The foundational work on Nix by Eelco Dolstra)

VIII. Additional Commands and Concepts Mentioned

* `nixos-rebuild switch`

* `nixos-rebuild boot`

* `nixos-rebuild test`

* `nix-channel --add`

* `nix-channel --update`

* `nix-env -iA` (for imperative package installation)

* `nix build`

* `nix shell`

IX. Music Credits

* Creo - Flow

* LAKEY INSPIRED - Blue Boi

* LAKEY INSPIRED - The Process

* Trance Music for Racing Game (dream speedr...

* 3 A.M Chill Session 🌌 [synthwave]

* LEMMiNO - Cipher (BGM)