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
• Completely portable
• 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 a same architecture Linux kernel and have a shell interpreter it will run. No external dependencies are required besides a compatible Linux kernel and a shell interpreter.

Some others to try:

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

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

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

Self-bundling

Startin 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 uses gzip compression and AppImage uses lzma compression. Anyway, you can 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.

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