NixOS¶

A powerful Linux distribution built on the Nix package manager, enabling reproducible, declarative system configurations.

🔧 🐧 Key Concepts & Features¶

🛠️ Declarative Configuration¶

System configuration is described in .nix files.
Rebuilding the system ensures consistency across reboots and devices.

📦 Nix Flakes¶

Flakes improve reproducibility and manage multiple configurations.

Use a flake reference like:

sudo nixos-rebuild switch --flake ./nixos/${hostname}

Replace ${hostname} manually if using templates (e.g., in Hyprland configs).

🧠 Use Case: Hyprland with ZaneyOS¶

Based on ZaneyOS.
Forked and adapted in your own pierreg branch.
Integration into flake system allows modular, theme-based configuration.

🧪 Useful Commands¶

# Rebuild and apply the configuration from the specified flake:
sudo nixos-rebuild switch --flake ./nixos/#pierreg

💻 My Experience: Simple (Re)Installation on a New Computer¶

I recently set up a new machine equipped with a discrete GPU for experimenting with GPU computing. It turned out to be a great opportunity to test how smooth it is to reinstall NixOS from scratch and replicate my existing setup.

✅ Conclusion¶

The entire process was surprisingly straightforward. I ended up with an identical environment to my previous system—complete with all my apps, custom configurations, Neovim setup, Tmux, personalized Hyprland shortcuts, and more.

🧭 Steps I Followed (dual boot with Windows)¶

Used Windows' partition manager to create a blank partition for NixOS
Entered BIOS to:
- Disable Secure Boot (since it doesn’t recognize NixOS)
- Set the USB stick with the NixOS installer as the first boot option
Installed NixOS with the GNOME desktop environment following the graphical installer
Opened a terminal and ran: nix-shell -p git vim
Cloned my dotfiles/configuration repository and navigated into it
Generated hardware configuration: nixos-generate-config --show-hardware-config > hosts/pierreg/hardware.nix
Enabled flake support: export NIX_CONFIG="experimental-features = nix-command flakes"
Rebuilt and switched to my full system config: sudo nixos-rebuild switch --flake .#pierreg

🔧 Final Touches¶

After installation, all I had to do was:

Connect my mail account in Thunderbird
Add my Git SSH keys
Log in to Firefox and sync my GitLab account
Re-download my Git repositories

🎮 Bonus: GPU Setup¶

As part of this install, I also took the time to learn how to configure hybrid GPU management (discrete + integrated), which has been valuable for both gaming and compute workloads.

🎛️ Desktop Environment & Audio¶

I'm using Hyprland as my Wayland compositor, which gives me a lightweight, dynamic tiling experience with great performance and flexibility.

To manage multiple displays easily, I use wdisplays, a simple GUI tool for configuring screen layouts on Wayland.

For audio, I'm currently using PulseAudio, which integrates well with most desktop apps and provides straightforward volume and device management.

📦 Tool Spotlight: `nix-shell -p pdfcpu`¶

🔍 What is `nix-shell`?¶

nix-shell creates a temporary shell environment where specified packages are available without installing them globally.

Perfect for: - Isolated testing - Short-lived tasks - Reproducible scripting

🧰 What does `-p pdfcpu` do?¶

The -p flag means “provide this package.”
This command:

nix-shell -p pdfcpu

...starts a new shell with the pdfcpu tool immediately available.

📄 What is `pdfcpu`?¶

pdfcpu is a fast, open-source CLI tool written in Go for managing PDF files.

Key capabilities: - ✅ Validate PDFs - 🔧 Optimize/compress files - 🔍 Extract images/pages - ✂️ Split/merge - 🖋️ Add watermarks or stamps

🌟 Why is this Cool?¶

🧼 No clutter: No need to install or clean up later.
🔁 Reproducible: Exact tool/version every time.
🧪 Safe testing: Temporary environment avoids polluting your system.
⚙️ Automation-friendly: Great for scripts and CI/CD.
💡 Portable: Easy to share your environment setup.

🚀 Example Usage¶

After running:

nix-shell -p pdfcpu

You can use:

pdfcpu validate input.pdf
pdfcpu optimize input.pdf output.pdf
pdfcpu extract -mode=images input.pdf ./images/

🧠 Notes & Tips¶

Always make sure to pin versions in your flake for true reproducibility.
Use direnv to automatically enter nix-shell environments in project directories.