nixos

NixOS is a Linux distribution that uses a unique, declarative approach to system configuration.

Instead of modifying configuration files directly, you define your entire system—packages, services, users, etc.—in a single file (configuration.nix). NixOS then builds the system from that declaration.

This provides three main benefits:

  1. Reproducibility: The same configuration file always produces the exact same system.
  2. Atomic Upgrades: System changes complete fully or not at all, preventing broken states.
  3. Rollbacks: You can instantly revert to any previous system configuration if something goes wrong.

This reproducibility also includes per-user settings via home-manager.