Nixology: A Practical guide to NixOS and flakes

"It works on my machine."

It is the most expensive sentence in software development. We have spent decades trying to fix it with version managers (nvm, pyenv, gvm), virtual environments (venv), and containers (Docker). But these are just bandages. Underneath, your operating system is still a mutable, fragile mess of global libraries and conflicting dependencies.

NixOS changes the paradigm.

It treats your entire operating system like a git commit. You declare the state you want in a text file, and Nix builds it. If it breaks? You revert to the previous "commit" in the boot menu. If you need to share a project? You share a file, and your colleague gets the exact same toolchain, bit-for-bit.

Why this guide?

Learning Nix is notoriously difficult. The learning curve is a vertical wall. The documentation is vast but often academic. The ecosystem is split between "legacy" commands (nix-env) and "modern" commands (nix flake). Tutorials often lead you down the wrong rabbit hole, teaching you methods that were deprecated three years ago.

Nixology is the pragmatic guide I wish I had.

This is not a deep dive into functional programming theory. This is a roadmap for developers who want to get work done. We take a "Flakes-First" approach, skipping the legacy confusion and going straight to the modern standard for reproducible builds.

The roadmap

We have broken this journey down into 9 core parts and several "Side Quests" for specific needs.

Phase 1: The Foundation

  • 01 Philosophy Why do we need reproducible builds? The difference between the "Construction Site" (Linux) and the "Blueprint" (NixOS).
  • 02 Installation Installing NixOS the right way. Understanding the Read-Only Store and the Safety Net (Generations).
  • 03 Nix Language A crash course in Nix syntax. No theory, just the patterns you need to configure your system.
  • 04 Configuration File Writing your first system blueprint. Managing users, packages, and unfree software.
  • 05 Basic commands Survival tools. How to update, clean garbage, and use temporary shells.

Phase 2: The Modern Workflow (Flakes)

  • 06 Flakes The turning point. Moving your config to Git and locking your dependencies for true reproducibility.
  • 07 Nix commands Mastering the modern tools: nix run, nix shell, and nix build.
  • 08 Development Environment The killer feature. Replacing Docker and NVM with project-specific development shells.
  • 09 Useful Scripts Scripts and workflows to make managing NixOS fast and ergonomic.

Side Quests (Optional)

Who is this for?

This series is written for Software Engineers and Power Users. You don't need to be a Linux wizard, but you should be comfortable with a terminal. If you are tired of fragile systems and want to reclaim control over your computing environment, you are in the right place.

Let's begin: 01 Philosophy