Installing a few packages from `master`

This article was originally published at https://gist.github.com/joepie91/ce9267788fdcb37f5941be5a04fcdd0f.

You probably want to install from unstable instead of master, and you probably want to do it differently than described here (eg. importing from URL or specifying it as a Flake). This documentation is kept here for posterity, as it is still helpful to understand how to import a local copy of a nixpkgs into your configuration.

1. git clone https://github.com/NixOS/nixpkgs.git /etc/nixos/nixpkgs-master
2. Edit your /etc/nixos/configuration.nix like this:

{ config, pkgs, ... }:

let
  nixpkgsMaster = import ./nixpkgs-master {};
  
  stablePackages = with pkgs; [
    # This is where your packages from stable nixpkgs go
  ];
  
  masterPackages = with nixpkgsMaster; [
    # This is where your packages from `master` go
    nodejs-6_x
  ];
in {
  # This is where your normal config goes, we've just added a `let` block
  
  environment = {
    # ...
    
    systemPackages = stablePackages ++ masterPackages;
  };
  
  # ...
}