NixOS : A Linux Distro

What is NixOS ?

NixOS is a Linux distribution that based on the Nix package manager. Unlike traditional distributions such as Ubuntu, Arch, or Fedora, where software installations modify system state unpredictably, NixOS ensures a consistent environment through declarative configuration management.

Nix Package Manager :The Nix Package Manager is a tool that installs and manages software very carefully. It keeps each program in its own “bubble,” so different versions of software won’t interfere with each other.

Features of NixOS : (Continued)

3. Atomic Upgrades and Rollbacks : Every change in NixOS creates a new generation of the system.If an update breaks something, you can instantly rollback to the previous working state using:

Unlike traditional package managers (APT, DNF, Pacman), where package upgrades can cause partial system failures, NixOS ensures atomic changes, meaning the system is always in a valid state.

4. Package Management Without System Pollution : Traditional Linux distros install software in shared directories (/usr/bin, /lib, etc.), which can lead to dependency conflicts.Nix uses a unique approach: every package and its dependencies are stored in the /nix/store with unique cryptographic hashes.

Features of NixOS : (Continued)

5. No More "Broken Systems" Due to Failed Updates : In traditional Linux distros, if an upgrade fails halfway, your system may become unusable. Updates are transactional, meaning either they complete successfully, or they don't apply at all.

6. User-Specific Environments (No Root Needed) : Users can install packages without root permissions, thanks to profiles. Each user gets a separate environment, reducing conflicts.
Example :
nix-env -iA nixpkgs.firefox

7. Garbage Collection : Since packages are immutable, old versions accumulate in /nix/store. You can remove unused packages with:
nix-collect-garbage -d

Use Cases for NixOS

1. DevOps & CI/CD : Ensures identical environments across developers’ machines and CI/CD pipelines. No "works on my machine" issues.

2. Software Development : Developers can use multiple versions of the same software without conflicts. Example: Having Python 2.7, 3.8, and 3.10 installed simultaneously.

3. System Administrators : Rollbacks and atomic updates make managing servers easier and safer.

4. Research and Science : Scientists needing reproducible computational environments benefit from the declarative approach.

5. Security : Since packages are immutable, there is less risk of accidental modification. No more accidental "rm -rf /usr/bin" disasters.

Downsides of NixOS

1. Steep Learning Curve: Nix’s functional programming language is unusual for system configurations. Learning to write configuration.nix takes time.

2. Smaller Community: Compared to Ubuntu, Fedora, or Arch, NixOS has a smaller user base. Finding help may take longer.

3. Storage Overhead: Since packages are stored uniquely with hashes, disk usage can be high. Regular garbage collection is needed.

Key Features of the Nix Language

The Nix language is a purely functional, domain-specific language (DSL) designed for declarative package management and system configuration. It is used primarily in Nix, NixOS, and Nixpkgs to define system states, package builds, and configurations.

• Purely Functional: No side effects, same input produces same output.
• Declarative: You describe the desired state, and Nix ensures it.
• Lazy Evaluation: Expressions evaluate only when needed.
• Strongly Typed: Works with integers, strings, lists, sets, functions, etc.
• Package-Oriented: Built to define and manage software dependencies cleanly.

How to create a nix package

Step 1: Create a Directory :

Step 2: Create a Bash Script