NixOS

NixOS is a Linux distribution based on the Nix package manager and build system. It supports reproducible and declarative system-wide configuration management as well as atomic upgrades and rollbacks, although it can additionally support imperative package and user management. In NixOS, all components of the distribution — including the kernel, installed packages and system configuration files — are built by Nix from pure functions called Nix expressions.
— NixOS Wiki

NixOS is my current favorite Linux distribution. I like their features and trying to use it everywhere where it’s possible. Arch Linux is also good (minimal), but I like the NixOS approach more.

Features

Declarative configuration model (Nix language, global configuration file).
Reliable and atomic upgrades (same result on different machines, atomic. upgrades which are resistant to power failures).
Rollbacks (boot menu with previous configurations).
Reproducible system configurations (easily clone system across many machines).
Source-based model with binary cache (flexible build configuration, change package options)
Consistency (rebuild all dependencies when core packages are updated).
Multi-user package management (users can install packages without root).
80,000 official packages (Nixpkgs), special packages with easily configurable options (NixOS options, > 10000 options).
Documentation and community (Guides and Tutorials, NixOS wiki, Discourse, Matrix, GitHub).

Cleanup old generations

Native nix commands:

nix-env --list-generations
 
nix-collect-garbage --delete-older-than 30d
# or nix-collect-garbage --delete-old
 
# recommeneded to sometimes run as sudo to collect additional garbage
# in my case it's very actual, since I use a lot system packages
sudo nix-collect-garbage --delete-older-than 30d
# or sudo nix-collect-garbage --delete-old
 
# After the garbage collection, you can run the following command to remove
# boot entries that are no longer valid:
sudo nixos-rebuild switch

TODO: own hey utility?

hey gc; sudo hey gc
sudo /run/current-system/bin/switch-to-configuration boot

Get revision/hash for fetchFromGitHub/fetchit

For example this repo: https://github.com/cli/cli

# SHA256
nix-shell -p nix-prefetch-git jq --run \
  "nix hash to-sri sha256:\$(nix-prefetch-git --url https://github.com/cli/cli --quiet --rev v2.20.2 | jq -r '.sha256')"
 
# sha256
nix-shell -p nix-prefetch-git jq --run \
  "nix hash to-sri sha256:\$(nix-prefetch-git --url https://github.com/iturdikulov/dwm-flexipatch --quiet | jq -r '.sha256')"
 
# REV
nix-shell -p nix-prefetch-git jq --run "nix-prefetch-git --url https://github.com/cli/cli --quiet --rev v2.20.2 | jq -r '.rev'"
 
# HASH
nix-shell -p nix-prefetch-git jq --run "nix-prefetch-git --url https://github.com/iturdikulov/dwm-flexipatch --quiet | jq -r '.hash'"

LD_LIBRARY_PATH issues

This can happen when importing python libraries: Solution: add ${stdenv.cc.cc.lib}/lib/libstdc++.so.6 to the LD_LIBRARY_PATH.

A sample shell.nix:

{ pkgs ? (import <nixpkgs> {}).pkgs }:
with pkgs;
mkShell {
  buildInputs = [
    python3Packages.virtualenv # run virtualenv .
    python3Packages.pyqt5 # avoid installing via pip
    python3Packages.pyusb # fixes the pyusb 'No backend available' when installed directly via pip
  ];
  shellHook = ''
    # fixes libstdc++ issues and libgl.so issues
    LD_LIBRARY_PATH=${stdenv.cc.cc.lib}/lib/:/run/opengl-driver/lib/
    # fixes xcb issues :
    QT_PLUGIN_PATH=${qt5.qtbase}/${qt5.qtbase.qtPluginPrefix}
  '';
}

PCI passthrough

Notes on PCI passthrough on NixOS using QEMU and VFIO
Review and add notes Virtiofs: Shared file system

TODO:

linux kernel flake + le9ec
test Plasma/Wayland
pipewire low-latency + rtkit

Inom Turdikulov