home-manager/README.md

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. It allows declarative configuration of user specific (non global) packages and dotfiles.

Before attempting to use Home Manager please read the warning below.

For a more systematic overview of Home Manager and its available options, please see the Home Manager manual.

Words of warning

Unfortunately, it is quite possible to get difficult to understand errors when working with Home Manager, such as infinite loops with no clear source reference. You should therefore be comfortable using the Nix language and the various tools in the Nix ecosystem. Reading through the Nix Pills document is a good way to familiarize yourself with them.

If you are not very familiar with Nix but still want to use Home Manager then you are strongly encouraged to start with a small and very simple configuration and gradually make it more elaborate as you learn.

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 overwritten was from a previous Home Manager generation or from manual configuration.

Home Manager targets NixOS unstable and NixOS version 21.05 (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. See the rollbacks section for instructions on how to manually perform a rollback.

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.

Contact

You can chat with us on IRC in the channel #home-manager on OFTC.

Installation

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

1. Make sure you have a working Nix installation. Specifically, make sure that your user is able to build and install Nix packages. For example, you should be able to successfully run a command like nix-instantiate '<nixpkgs>' -A hello without having to switch to the root user. For a multi-user install of Nix this means that your user must be covered by the allowed-users Nix option. On NixOS you can control this option using the nix.allowedUsers system option.

   Note that Nix 2.4 (nixUnstable) is not yet supported.

2. Add the appropriate Home Manager channel. If you are following Nixpkgs master or an unstable channel you can run

   $ nix-channel --add https://github.com/nix-community/home-manager/archive/master.tar.gz home-manager
   $ nix-channel --update
   

   and if you follow a Nixpkgs version 21.05 channel you can run

   $ nix-channel --add https://github.com/nix-community/home-manager/archive/release-21.05.tar.gz home-manager
   $ nix-channel --update
   

   On NixOS you may need to log out and back in for the channel to become available. On non-NixOS you may have to add

   export NIX_PATH=$HOME/.nix-defexpr/channels${NIX_PATH:+:}$NIX_PATH
   

   to your shell (see nix#2033).

3. Install Home Manager and create the first Home Manager generation:

   $ nix-shell '<home-manager>' -A install
   

   Once finished, Home Manager should be active and available in your user environment.

4. If you do not plan on having Home Manager manage your shell configuration then you must source the

   $HOME/.nix-profile/etc/profile.d/hm-session-vars.sh
   

   file in your shell configuration. This file can be sourced directly by POSIX.2-like shells such as Bash or Z shell. Fish users can use utilities such as foreign-env or babelfish.

   For example, if you use Bash then add

   . "$HOME/.nix-profile/etc/profile.d/hm-session-vars.sh"
   

   or this when managing home configuration together with system configuration

   . "/etc/profiles/per-user/$USER/etc/profile.d/hm-session-vars.sh"
   

   to your ~/.profile file.

If instead of using channels you want to run Home Manager from a Git checkout of the repository then you can use the programs.home-manager.path option to specify the absolute path to the repository.

Usage

Home Manager is typically managed through the home-manager tool. This tool can, for example, apply configurations to your home directory, list user packages installed by the tool, and list the configuration generations.

As an example, let us expand the initial configuration file from the installation above to install the htop and fortune packages, install Emacs with a few extra packages enabled, install Firefox with smooth scrolling disabled, and enable the user gpg-agent service.

To satisfy the above setup we should elaborate the ~/.config/nixpkgs/home.nix file as follows:

{ pkgs, ... }:

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

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

  programs.firefox = {
    enable = true;
    profiles = {
      myprofile = {
        settings = {
          "general.smoothScroll" = false;
        };
      };
    };
  };

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

  programs.home-manager = {
    enable = true;
    path = "…";
  };
}

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.

Documentation of available configuration options, including descriptions and usage examples, is available in the Home Manager manual or offline by running

$ man home-configuration.nix

Rollbacks

While the home-manager tool does not explicitly support rollbacks at the moment it is relatively easy to perform one manually. The steps to do so are

1. Run home-manager generations to determine which generation you wish to rollback to:

   $ home-manager generations
   2018-01-04 11:56 : id 765 -> /nix/store/kahm1rxk77mnvd2l8pfvd4jkkffk5ijk-home-manager-generation
   2018-01-03 10:29 : id 764 -> /nix/store/2wsmsliqr5yynqkdyjzb1y57pr5q2lsj-home-manager-generation
   2018-01-01 12:21 : id 763 -> /nix/store/mv960kl9chn2lal5q8lnqdp1ygxngcd1-home-manager-generation
   2017-12-29 21:03 : id 762 -> /nix/store/6c0k1r03fxckql4vgqcn9ccb616ynb94-home-manager-generation
   2017-12-25 18:51 : id 761 -> /nix/store/czc5y6vi1rvnkfv83cs3rn84jarcgsgh-home-manager-generation
   …
   

2. Copy the Nix store path of the generation you chose, e.g.,

   /nix/store/mv960kl9chn2lal5q8lnqdp1ygxngcd1-home-manager-generation
   

   for generation 763.

3. Run the activate script inside the copied store path:

   $ /nix/store/mv960kl9chn2lal5q8lnqdp1ygxngcd1-home-manager-generation/activate
   Starting home manager activation
   …
   

Keeping your ~ safe from harm

To configure programs and services 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 ~/.config/git/config 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/.config/git/config' 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.command = "…";

  # …
}

in your Home Manager configuration.

Nix Flakes

Home Manager includes a flake.nix file for compatibility with Nix Flakes for those that wish to use it as a module. A bare-minimum flake.nix would be as follows:

{
  description = "NixOS configuration";

  inputs = {
    nixpkgs.url = "github:nixos/nixpkgs/nixos-unstable";
    home-manager.url = "github:nix-community/home-manager";
  };

  outputs = { home-manager, nixpkgs, ... }: {
    nixosConfigurations = {
      hostname = nixpkgs.lib.nixosSystem {
        system = "x86_64-linux";
        modules = [
          ./configuration.nix
          home-manager.nixosModules.home-manager
          {
            home-manager.useGlobalPkgs = true;
            home-manager.useUserPackages = true;
            home-manager.users.jdoe = import ./home.nix;
          }
        ];
      };
    };
  };
}

Note, the Home Manager library is exported by the flake under lib.hm.

When using flakes, switch to new configurations as you do for the whole system (e. g. nixos-rebuild switch --flake <path>) instead of using the home-manager command line tool.

Releases

Home Manager is developed against nixpkgs-unstable branch, which often causes it to contain tweaks for changes/packages not yet released in stable NixOS. To avoid breaking users' configurations, Home Manager is released in branches corresponding to NixOS releases (e.g. release-21.05). These branches get fixes, but usually not new modules. If you need a module to be backported, then feel free to open an issue.