nix-channels

Summary

• a channel is a collection of package definitions that are made available for installation
• these package definitions are stored in a repository, which can be accessed via the internet or a local file system
• are used to manage and distribute packages within a Nix installation
• they allow users to install packages from a variety of sources, such as the official Nixpkgs repository or third-party repositories
• to add the official Nixpkgs channel

  nix-channel --add https://nixos.org/channels/nixpkgs-unstable