Home Manager using Nix

This project provides a basic system for managing a user environment using the Nix package manager together with the Nix libraries found in Nixpkgs. Before attempting to use Home Manager please read the warning below.

Words of warning

This project is under development. I personally use it to manage several user configurations but it may fail catastrophically for you. So beware!

In some cases Home Manager cannot detect whether it will overwrite a previous manual configuration. For example, the Gnome Terminal module will write to your dconf store and cannot tell whether a configuration that it is about to be overwrite was from a previous Home Manager generation or from manual configuration.

Home Manager targets NixOS version 17.03 (the current stable version), it may or may not work on other Linux distributions and NixOS versions.

Also, the home-manager tool does not explicitly support rollbacks at the moment so if your home directory gets messed up you'll have to fix it yourself (you can attempt to run the activation script for the desired generation).

Now when your expectations have been built up and you are eager to try all this out you can go ahead and read the rest of this text.

Installation

Currently the easiest way to install Home Manager is as follows:

1. Make sure you have a working Nix installation. If you are not using NixOS then you may here have to run

   $ mkdir -m 0755 -p /nix/var/nix/{profiles,gcroots}/per-user/$USER
   

   since Home Manager uses these directories to manage your profile generations. On NixOS these should already be available.

2. Clone the Home Manager repository into the ~/.nixpkgs directory:

   $ git clone https://github.com/rycee/home-manager ~/.nixpkgs/home-manager
   

3. Add Home Manager to your user's Nixpkgs, for example by adding it to the packageOverrides section in your ~/.nixpkgs/config.nix file:

   {
     packageOverrides = pkgs: rec {
       home-manager = import ./home-manager { inherit pkgs; };
     };
   }
   

4. Install the home-manager package:

   $ nix-env -f '<nixpkgs>' -iA home-manager
   installing ‘home-manager’
   

Usage

The home-manager package installs a tool that is conveniently called home-manager. This tool can apply configurations to your home directory, list user packages installed by the tool, and list the configuration generations.

As an example, let us set up a very simple configuration that installs the htop and fortune packages, installs Emacs with a few extra packages enabled, installs Firefox with Adobe Flash enabled, and enables the user gpg-agent service.

First create a file ~/.nixpkgs/home.nix containing

{ pkgs, ... }:

{
  home.packages = [
    pkgs.htop
    pkgs.fortune
  ];

  programs.emacs = {
    enable = true;
    extraPackages = epkgs: [
      epkgs.nix-mode
      epkgs.magit
    ];
  };

  programs.firefox = {
    enable = true;
    enableAdobeFlash = true;
  };

  services.gpg-agent = {
    enable = true;
    defaultCacheTtl = 1800;
    enableSshSupport = true;
  };
}

To activate this configuration you can then run

$ home-manager switch

or if you are not feeling so lucky,

$ home-manager build

which will create a result link to a directory containing an activation script and the generated home directory files.

File safety

To configure programs and services the Home Manager must write various things to your home directory. To prevent overwriting any existing files when switching to a new generation, Home Manager will attempt to detect collisions between existing files and generated files. If any such collision is detected the activation will terminate before changing anything on your computer.

For example, suppose you have a wonderful, painstakingly created ~/.gitconfig and add

{
  # …

  programs.git = {
    enable = true;
    userName = "Jane Doe";
    userEmail = "jane.doe@example.org";
  };

  # …
}

to your configuration. Attempting to switch to the generation will then result in

$ home-manager switch
…
Activating checkLinkTargets
Existing file '/home/jdoe/.gitconfig' is in the way
Please move the above files and try again

Graphical services

Home Manager includes a number of services intended to run in a graphical session, for example xscreensaver and dunst. Unfortunately, such services will not be started automatically unless you let Home Manager start your X session. That is, you have something like

{
  # …

  services.xserver.enable = true;

  # …
}

in your system configuration and

{
  # …

  xsession.enable = true;
  xsession.windowManager = "…";

  # …
}

in your Home Manager configuration.