Pinning Nixpkgs#

Specifying remote Nix expressions, such as the one provided by Nixpkgs, can be done in several ways:

Possible URL values#

  • Local file path:

    ./path/to/expression.nix
    

    Using ./. means that the expression is located in a file default.nix in the current directory.

  • Pinned to a specific commit:

    https://github.com/NixOS/nixpkgs/archive/eabc38219184cc3e04a974fe31857d8e0eac098d.tar.gz
    
  • Using the latest channel version, meaning all tests have passed:

    http://nixos.org/channels/nixos-22.11/nixexprs.tar.xz
    
  • Shorthand syntax for channels:

    channel:nixos-22.11
    
  • Using the latest channel version, hosted by GitHub:

    https://github.com/NixOS/nixpkgs/archive/nixos-22.11.tar.gz
    
  • Using the latest commit on the release branch, but not tested yet:

    https://github.com/NixOS/nixpkgs/archive/release-21.11.tar.gz
    

Examples#

  • $ nix-build -I ~/dev
    
  • $ nix-build -I nixpkgs=http://nixos.org/channels/nixos-22.11/nixexprs.tar.xz
    
  • $ nix-build -I nixpkgs=channel:nixos-22.11
    
  • $ NIX_PATH=nixpkgs=http://nixos.org/channels/nixos-22.11/nixexprs.tar.xz nix-build
    
  • $ NIX_PATH=nixpkgs=channel:nixos-22.11 nix-build
    
  • In the Nix language:

    1let
    2  pkgs = import (fetchTarball "https://github.com/NixOS/nixpkgs/archive/nixos-22.11.tar.gz") {};
    3in pkgs.stdenv.mkDerivation { ... }