These chapters includes some notes that apply to specific packages and should answer some of the frequently asked questions related to Nixpkgs use. Some useful information related to package use can be found in package-specific development notes.

Packages that use OpenGL have NixOS desktop as their primary target. The current solution for loading the GPU-specific drivers is based on libglvnd and looks for the driver implementation in LD_LIBRARY_PATH. If you are using a non-NixOS GNU/Linux/X11 desktop with free software video drivers, consider launching OpenGL-dependent programs from Nixpkgs with Nixpkgs versions of libglvnd and mesa_drivers in LD_LIBRARY_PATH. For proprietary video drivers you might have luck with also adding the corresponding video driver package.

To allow simultaneous use of packages linked against different versions of glibc with different locale archive formats Nixpkgs patches glibc to rely on LOCALE_ARCHIVE environment variable. On non-NixOS distributions this variable is obviously not set. This can cause regressions in language support or even crashes in some Nixpkgs-provided programs. The simplest way to mitigate this problem is exporting the LOCALE_ARCHIVE variable pointing to ${glibcLocales}/lib/locale/locale-archive. The drawback (and the reason this is not the default) is the relatively large (a hundred MiB) size of the full set of locales. It is possible to build a custom set of locales by overriding parameters allLocales and locales of the package.

The Emacs package comes with some extra helpers to make it easier to configure. emacsWithPackages allows you to manage packages from ELPA. This means that you will not have to install that packages from within Emacs. For instance, if you wanted to use company, counsel, flycheck, ivy, magit, projectile, and use-package you could use this as a ~/.config/nixpkgs/config.nix override: { packageOverrides = pkgs: with pkgs; { myEmacs = emacsWithPackages (epkgs: (with epkgs.melpaStablePackages; [ company counsel flycheck ivy magit projectile use-package ])); } } You can install it like any other packages via nix-env -iA myEmacs. However, this will only install those packages. It will not configure them for us. To do this, we need to provide a configuration file. Luckily, it is possible to do this from within Nix! By modifying the above example, we can make Emacs load a custom config file. The key is to create a package that provide a default.el file in /share/emacs/site-start/. Emacs knows to load this file automatically when it starts. { packageOverrides = pkgs: with pkgs; rec { myEmacsConfig = writeText "default.el" '' ;; initialize package (require 'package) (package-initialize 'noactivate) (eval-when-compile (require 'use-package)) ;; load some packages (use-package company :bind ("<C-tab>" . company-complete) :diminish company-mode :commands (company-mode global-company-mode) :defer 1 :config (global-company-mode)) (use-package counsel :commands (counsel-descbinds) :bind (([remap execute-extended-command] . counsel-M-x) ("C-x C-f" . counsel-find-file) ("C-c g" . counsel-git) ("C-c j" . counsel-git-grep) ("C-c k" . counsel-ag) ("C-x l" . counsel-locate) ("M-y" . counsel-yank-pop))) (use-package flycheck :defer 2 :config (global-flycheck-mode)) (use-package ivy :defer 1 :bind (("C-c C-r" . ivy-resume) ("C-x C-b" . ivy-switch-buffer) :map ivy-minibuffer-map ("C-j" . ivy-call)) :diminish ivy-mode :commands ivy-mode :config (ivy-mode 1)) (use-package magit :defer :if (executable-find "git") :bind (("C-x g" . magit-status) ("C-x G" . magit-dispatch-popup)) :init (setq magit-completing-read-function 'ivy-completing-read)) (use-package projectile :commands projectile-mode :bind-keymap ("C-c p" . projectile-command-map) :defer 5 :config (projectile-global-mode)) ''; myEmacs = emacsWithPackages (epkgs: (with epkgs.melpaStablePackages; [ (runCommand "default.el" {} '' mkdir -p $out/share/emacs/site-lisp cp ${myEmacsConfig} $out/share/emacs/site-lisp/default.el '') company counsel flycheck ivy magit projectile use-package ])); }; } This provides a fairly full Emacs start file. It will load in addition to the user's presonal config. You can always disable it by passing -q to the Emacs command. Sometimes emacsWithPackages is not enough, as this package set has some priorities imposed on packages (with the lowest priority assigned to Melpa Unstable, and the highest for packages manually defined in pkgs/top-level/emacs-packages.nix). But you can't control this priorities when some package is installed as a dependency. You can override it on per-package-basis, providing all the required dependencies manually - but it's tedious and there is always a possibility that an unwanted dependency will sneak in through some other package. To completely override such a package you can use overrideScope'. overrides = self: super: rec { haskell-mode = self.melpaPackages.haskell-mode; ... }; ((emacsPackagesGen emacs).overrideScope' overrides).emacsWithPackages (p: with p; [ # here both these package will use haskell-mode of our own choice ghc-mod dante ])

DLib is a modern, C++-based toolkit which provides several machine learning algorithms.

Especially older CPUs don't support AVX (Advanced Vector Extensions) instructions that are used by DLib to optimize their algorithms. On the affected hardware errors like Illegal instruction will occur. In those cases AVX support needs to be disabled: self: super: { dlib = super.dlib.override { avxSupport = false; }; }

All users of Nixpkgs are free software users, and many users (and developers) of Nixpkgs want to limit and tightly control their exposure to unfree software. At the same time, many users need (or want) to run some specific pieces of proprietary software. Nixpkgs includes some expressions for unfree software packages. By default unfree software cannot be installed and doesn’t show up in searches. To allow installing unfree software in a single Nix invocation one can export NIXPKGS_ALLOW_UNFREE=1. For a persistent solution, users can set allowUnfree in the Nixpkgs configuration. Fine-grained control is possible by defining allowUnfreePredicate function in config; it takes the mkDerivation parameter attrset and returns true for unfree packages that should be allowed.

Steam is distributed as a .deb file, for now only as an i686 package (the amd64 package only has documentation). When unpacked, it has a script called steam that in Ubuntu (their target distro) would go to /usr/bin . When run for the first time, this script copies some files to the user's home, which include another script that is the ultimate responsible for launching the steam binary, which is also in $HOME. Nix problems and constraints: We don't have /bin/bash and many scripts point there. Similarly for /usr/bin/python . We don't have the dynamic loader in /lib . The steam.sh script in $HOME can not be patched, as it is checked and rewritten by steam. The steam binary cannot be patched, it's also checked. The current approach to deploy Steam in NixOS is composing a FHS-compatible chroot environment, as documented here. This allows us to have binaries in the expected paths without disrupting the system, and to avoid patching them to work in a non FHS environment.

For 64-bit systems it's important to have hardware.opengl.driSupport32Bit = true; in your /etc/nixos/configuration.nix. You'll also need hardware.pulseaudio.support32Bit = true; if you are using PulseAudio - this will enable 32bit ALSA apps integration. To use the Steam controller or other Steam supported controllers such as the DualShock 4 or Nintendo Switch Pro, you need to add hardware.steam-hardware.enable = true; to your configuration.

Steam fails to start. What do I do? Try to run strace steam to see what is causing steam to fail. Using the FOSS Radeon or nouveau (nvidia) drivers The newStdcpp parameter was removed since NixOS 17.09 and should not be needed anymore. Steam ships statically linked with a version of libcrypto that conflics with the one dynamically loaded by radeonsi_dri.so. If you get the error steam.sh: line 713: 7842 Segmentation fault (core dumped) have a look at this pull request. Java There is no java in steam chrootenv by default. If you get a message like /home/foo/.local/share/Steam/SteamApps/common/towns/towns.sh: line 1: java: command not found You need to add steam.override { withJava = true; }; to your configuration.

The FHS-compatible chroot used for steam can also be used to run other linux games that expect a FHS environment. To do it, add pkgs.(steam.override { nativeOnly = true; newStdcpp = true; }).run to your configuration, rebuild, and run the game with steam-run ./foo

Please note that the citrix_receiver package has been deprecated since its development was discontinued by upstream and will be replaced by the citrix workspace app. Citrix Receiver and Citrix Workspace App are a remote desktop viewers which provide access to XenDesktop installations.

The tarball archive needs to be downloaded manually as the license agreements of the vendor for Citrix Receiver or Citrix Workspace need to be accepted first. Then run nix-prefetch-url file://$PWD/linuxx64-$version.tar.gz. With the archive available in the store the package can be built and installed with Nix. It's recommended to install Citrix Receiver and/or Citrix Workspace using nix-env -i or globally to ensure that the .desktop files are installed properly into $XDG_CONFIG_DIRS. Otherwise it won't be possible to open .ica files automatically from the browser to start a Citrix connection.

The Citrix Receiver and Citrix Workspace App in nixpkgs trust several certificates from the Mozilla database by default. However several companies using Citrix might require their own corporate certificate. On distros with imperative packaging these certs can be stored easily in $ICAROOT, however this directory is a store path in nixpkgs. In order to work around this issue the package provides a simple mechanism to add custom certificates without rebuilding the entire package using symlinkJoin: { config.allowUnfree = true; }; let extraCerts = [ ./custom-cert-1.pem ./custom-cert-2.pem /* ... */ ]; in citrix_workspace.override { # the same applies for `citrix_receiver` if used. inherit extraCerts; }]]>