nix-bundle

nix-bundle is a way to package Nix attributes into single-file executables.

Benefits

• Single-file output
• Can be run by non-root users
• No runtime
• Distro agnostic
• No installation

Getting started

Make sure you have installed Nix already. See http://nixos.org/nix/ for more details.

Once you have a working Nix install, you can run:

$ ./nix-bundle.sh hello /bin/hello

hello indicates the Nix derivation from NixPkgs that you want to use, while /bin/hello indicates the path of the executable relative to hello that you want to run. This will create the file "hello". Running it:

$ ./hello
Hello, world!

This is a standalone file that is completely portable! As long as you are running the same architecture Linux kernel and have a shell interpreter available it will run.

Some others to try:

./nix-bundle.sh nano /bin/nano

./nix-bundle.sh emacs /bin/emacs

Or if you want to try graphical applications:

# Simple X game. Very few dependencies. Quick to build and load. ~13MB
./nix-bundle.sh xskat /bin/xskat

./nix-bundle.sh firefox /bin/firefox

# SDL-based game. ~228MB
./nix-bundle.sh ivan /bin/ivan

Self-bundling (meta)

Starting with v0.1.3, you can bundle nix-bundle! To do this, just use nix-bundle normally:

NIX_PATH="nixpkgs=https://github.com/matthewbauer/nixpkgs/archive/nix-bundle.tar.gz" ./nix-bundle.sh nix-bundle /bin/nix-bundle

[Experimental] Create AppImage executables from Nix expressions

"nix-bundle.sh" tends to create fairly large outputs. This is largely because nix-bundle.sh "extracts" its payload up front. AppImage uses a different method where extraction only takes place when the file is accessed (through FUSE and SquashFS). You can now create a compliant "AppImage" using the "nix2appimage.sh" script:

./nix2appimage.sh emacs

This will create a file at Emacs-x86_64.AppImage which you can execute.

Notice that there is only one argument for nix2appimage.sh. This is because the target executable will be detected from the .desktop file in /share/applications/*.desktop. As a side-effect, AppImage requires your package to have a .desktop file, so packages like "hello", "coreutils", etc. will not work.

Some other examples to try:

./nix2appimage.sh firefox

./nix2appimage.sh vlc

./nix2appimage.sh 0ad

./nix2appimage.sh wireshark-gtk

These may take a while because of the large closure size.

Note that these do not currently work out of the box with NixOS. Other Linux distros should work.

Comparison with AppImage, FlatPak, Snappy

Name	Distro-agnostic	Runtime required	Root required	Storage
nix-bundle	yes	no	no	Arx tarball
AppImage	yes	no	no	Squashfs w/ lzma compression
FlatPak	yes	yes	no	?
Snappy	yes	yes	no	squashFS

How it works

Nix-bundle glues together four different projects to work correctly:

• Arx - an archive execution tool
• Creates single-file archive executable that can unpack themselves and then run some command. nix-bundle calls nix-user-chroot to bootstrap the Nix environment. It outputs a "./nix" folder.
• nix-user-chroot - a small bootstrap that uses Linux namespaces to call chroot
  • This will create sub namespace and bind mount the "./nix" to "/nix" so that the Nix references function properly.
• Nix - a functional package manager
  • Used to build runtime closures that are self-contained.
• nixpkgs
  • Provides lots of different packages to choose from.

Drawbacks

Nix-bundle has some drawbacks that need to be worked on:

• Slow startup
• Large files (Firefox 150MB)
• Only compatible Linux
• Outputs built on x86-64 will not run on i386
• Requires Linux kernel with CAP_SYS_USER_NS on and permissions setup correctly