Introduction

Nix and NixOS are 2 exceptional tools that I use daily. It allows declarative environments and reproducibility that most of the users praise, favour and want.

Let me provide you with materials of them first: Nix Wiki, Nix Source, Nix and NixOS website, NixOS Wiki, NixOS Source, Nix and NixOS group on Github, these are the websites you may be interested to visit.

Let me introduce you to Nix and NixOS, Nix is both a programming language and a package manager. NixOS is an operating system based on Linux and Nix package manager and Nix language. However, Nix can also be installed on multiple OS and hosts, some notable exmaples are: Darwin-based(MacOS/OSX), other Linux-based operating systems, some BSD-based systems(OpenBSD and FreeBSD).

Nix Introduction

Nix is a purely functional programming language which means that it is mostly based on functions, similar to OCaml and Haskell. Nix as the package manager uses Nixpkgs, and Nixpkgs offers a wide selection of packages, surpassing AUR(~80k), Homebrew. Nixpkgs package count is ~120k.

NixOS Introduction

NixOS is also exceptional operating system. Commonly paired with Btrfs filesystem that allow rollbacks. For example, when a package breaks, you can always rollback to the previous generation of the built system. It utilizes Nix, by having /etc/nixos folder, it contains hardware-configuration.nix, configuration.nix, home.nix(optional), flake.nix(optional), flake.lock(optional, used with flake.nix).

NixOS and Nix are often considered hard to use, by with some ideas in mind, it will be easier.

Pre-Installation Guide

Before installing NixOS, it is good to know some things:

• First, you usually do not install packages imperatively(through processes), you declare what your system is going to be
• You have a wide selection of tools, but do not overwhelm yourself with them first
• If you choose to erase a disk, backup things as the first experience for NixOS is best carried out on an empty drive
• Rollbacks are available!
• You have many packages available!

Installation Guide

Obtaining Image

Let’s dive right into the installation now, without further ado. First, let’s proceed to the installation page and head to the NixOS Graphical ISO Image section and install your with your CPU arch, whether ARM64(aarch64) or AMD64(x86_64).

Flashing

Before booting into the graphical installer for NixOS, you should flash the image onto the drive first.

• If you are on Linux, use:

lsblk
# find the correct drive, eg /dev/sda
sudo umount /dev/sdX* 
# unmount any mounted partitions, eg /dev/sda1
sudo dd bs=4M conv=fsync oflag=direct status=progress if=<path-to-image> of=/dev/sdX 
# flash the image onto the desired drive

• If you are on Windows, use Rufus, with DD mode, ISO mode will not work properly when I tested.
• If you are on MacOS(OSX), use:

diskutil list 
# find the correct drive, eg /dev/disk1
diskutil unmountDisk /dev/disk[number] 
# unmount any mounted partitions, eg /dev/disk1s1
sudo dd bs=4M conv=fsync oflag=direct status=progress if=<path-to-image> of=/dev/sdX 
# flash the image, hopefully works

Booting into NixOS

Now that you have flashed the image and are ready to go. Check what your boot key is, often F9-12, Del, or ESC. Then reboot your system by either finding a button or via:

sudo reboot # on Linux

After that, smash your boot key like crazy, and you will be prompted with a screen that has input devices. Choose the desired drive that you flashed the image onto, and press the Enter key.

Again, you will be prompted with a screen that probably displays the selection for interface and respective kernel versions. The ones are probably: GNOME with latest kernel, GNOME with LTS kernel, KDE with latest kernel, KDE with LTS kernel. And for whatever one you choose, it does not affect what your system is going to be. For this example, I am choosing GNOME, while you can choose any one of them.

Testing NixOS

You are in NixOS probably by now. You should first be prompted with an Installer. It guides you through things, but do not interact with it just yet. First, you can inspect the environment, one thing that I like to do is to test something, for example(if you have a drive that has enough size, eg >8GB):

# Open your terminal first, whether GNOME terminal or Ptyxis in KDE
nix-shell -p fastfetch 
# This is nix-shell, it allows you to test tools that can be cleaned later
# After some time waiting, you can do fastfetch
fastfetch
# Now you can exit the shell and the terminal
exit
# Close the terminal

And now once you try to open the terminal again and try fastfetch, it is not viable, as software are stored differently, I will explain that later on. Now, you can try to inspect some simple /etc/nixos/configuration.nix config that online users or AI have to consider for the final time. If yes, then proceed onto the installer and install. You will be guided through Timezone, Locales(Best to set US English as primary locale for system, excluding Dates, etc.).

Then comes your Desktop Environment, the most supported two DEs are KDE Plasma and GNOME. You can also choose options like XFCE, or No Desktop for a minimal system or for Window Manager and Compositor setups. However, scripting configs for Window Managers like Sway and Hyprland are kind of tedious, you have to write every single keybind, features, etc. As there are no default config for Window Managers, usually. So I recommend KDE Plasma or GNOME.

Later your users, and disk configuration(use entire disk) and in that choose BTRFS filesystem, it is crucial and you can have Swap. Then just proceed, and shortly, after ~10min, you can reboot.

Closure

Now with a new system, you can try edit /etc/nixos/configuration.nix briefly, for more guides, please take a look at my second article regarding NixOS.