NixOS important commands

After I distro hopped from Archlinux to NixOS, I’ve been having to learn the Nix ecosystem and package management commands. I’ve found the migration from Archlinux to NixOS OK, but I am still struggling remembering some important Nix commands.

Updating packages #

sudo nix-channel --update -vv to update to the latest nix channel. This will essentially pull nixos-unstable and nixpkgs-unstable.

nix flake update Will update my flake.lock file with the latest version.

Rebuilding machine #

sudo nixos-rebuild switch --flake /home/seds/workspace/dotfiles/.#default rebuilds and applies latest changes/updates.

Diffing builds #

nvd diff /run/current-system result will diff the curren system with the recent build result. Handy to keep track what changed between rebuilds.

List generations #

nix-env --list-generations will list all existing builds.

Garbage collect generations #

nix-collect-garbage -d will garbage collect old generations.

Start a shell with a specific package #

nix-shell -p <package> will start a shell with <package> installed.

Run a custom nix-shell #

nix-shell python-poetry.nix --command zsh will execute python-poetry.nix shell and drop you into a zsh shell.