tl;dr; omnibin is a FUSE filesystem that puts every binary nixpkgs ever shipped on your $PATH. Nothing is installed. Nothing needs building. 0 bytes on disk until something actually reads a file. 😈
It’s 2026, why am I still installing packages individually?<sup>1</sup>1Yes, I am a little inspired after watching DHH’s keynote at RailsConf 2026. I feel the same way about package management.
\nWhy must I go through the ritual of adding a package to my configuration.nix, running nix-shell or succumb to the hellscape of nix-env -iA.
Nix gives us the power of having packages installed side-by-side without conflict. Why do I have to pick which ones I want to install?
\nWhy can’t I just have them all?
\nWhat if the machine just had all of them?
\n$ nix run github:fzakaria/omnibin\nomnibin: tree at /run/user/1000/omnibin, cache at /home/you/.cache/omnibin\n$ ls /omnibin/bin | wc -l\n51468\n$ python3 --version\nPython 3.14.6\n$ python3@3.6.2 --version\nPython 3.6.2That is over fifty thousand<sup>2</sup>2There are actually 881,933 binaries in the tree, but ls /omnibin/bin only lists the latest version of each binary. The versioned forms are still available, but they are not listed. top-level binaries available on my $PATH, from 2013 to 2026 built by Nixpkgs, available on-demand, without installing anything.
This is the magic 🧙♂️ of Nix, but it’s not restricted to Nix.
\nEveryone seems to still love Docker and OCI, why am I still picking which base image to use? Why can’t I just have them all?
\n# syntax=docker/dockerfile:1\nFROM fmzakari/omnibin:latest\nCOPY <<'SH' /demo.sh\npython3@3.6.2 -c 'import sys; print(sys.version.split()[0])'\njq --version\ngcc@10.2.0 --version | head -1\nSH\nCMD ["bash", "/demo.sh"]Is this the ultimate agent harness? It’s a container with everything in it, right from the start. Try it at fmzakari/omnibin.
\n$ docker build -t example .\n$ docker run --rm --device /dev/fuse --cap-add SYS_ADMIN example\n3.6.2\njq-1.8.1\ngcc (GCC) 10.2.0Of course, I cannot forget our NixOS friends. You no longer have to curate your environment.systemPackages or home.packages, you can just have them all.
{\n imports = [ inputs.omnibin.nixosModules.default ];\n services.omnibin.enable = true;\n}What is “package management” if every package is already installed?
\nTurns out that Hydra writes a .ls file next to every single narinfo on cache.nixos.org that describes the contents of the archive as JSON:
$ curl -s --compressed https://cache.nixos.org/3n4qphl9s728sz8frmpqqrv9b1m87g68.ls | jq\n{\n "root": {\n "entries": {\n "bin": {\n "entries": {\n "python3": { "target": "python3.14", "type": "symlink" },\n "python3.14": { "executable": true, "size": 14264, "type": "regular" }That metadata turns out to be the perfect index for a FUSE filesystem that can lazily fetch the NARs from the cache and unpack them on-demand. 🤓
\nNone of this would mean anything without nixpkgs-multiverse, which already resolves any (attribute, version) in nixpkgs history to the store path Hydra built for it on cache.nixos.org.
When you combine the two, you get a filesystem that can answer the question “where is python3@3.6.2” and then fetch it from the cache and unpack it for you, all without ever having to install it.
I crawled all of it the .ls files in under twelve minutes. 🤯
Once you have that, the filesystem writes itself:
\n$ ls /nix/store/2lb6nn8ivk1alhckv43n7734lqwbw7h9-python3-3.6.2/bin\n2to3 idle pydoc python python3.6 python3-config pyvenv\n2to3-3.6 idle3 pydoc3 python3 python3.6-config python-config pyvenv-3.6\n idle3.6 pydoc3.6 python3.6m python3.6m-configThat is CPython 3.6.2, from 2017. That ls downloaded nothing, it is answered from the pre-crawled index.
ls the treeAgents are “a thing”. Making them useful is a thing. Making them useful without installing anything is a thing.
\nIf your agent tried to ls /omnibin/bin and stat every single entry, it would have a really bad time. There are 881,933 binaries in the tree, and it would take a long time to stat them all.
To help the agents out a bit, ls /omnibin/bin lists only the bare names, one per executable, each resolving to the newest package that provides it.
The versioned forms all resolve, but they are not listed. For example, python3 resolves to the latest Python 3, which is 3.14.6 at the time of writing, but python3@3.6.2 resolves to the 2017 version.
For everything else there is the index, which is sitting right there in the mount:
\n$ sqlite3 /omnibin/index.db \\\n "SELECT attr, version\n FROM bins\n WHERE name = 'python3'\n ORDER BY version"That UX is a little rough, so you can also use the omnibin CLI to query the index:
$ omnibin which python3\n/nix/store/gxzhl7aaiid7zp3y47jqqiq7zg5mqpwp-python3-3.14.6/bin/python3\n$ omnibin which --all python3 | wc -l\n610\n$ omnibin which --all ffmpeg | head -2\nffmpeg@3.1.7 ffmpeg 0.4 MB /nix/store/0adpc3…-ffmpeg-3.1.7-bin/bin/ffmpeg\nffmpeg@3.2.4 ffmpeg 0.4 MB /nix/store/nhfgdv…-ffmpeg-3.2.4-bin/bin/ffmpegLastly, there is a /omnibin/README.md whose entire job is to tell whatever is exploring the filesystem to stop exploring the filesystem and query the database instead. 🤖
\nAt this point it should be obvious, but you pay for this on startup for the first access.
\n$ time python3@3.6.2 -c 'import sys; print(sys.version.split()[0])'\n3.6.2\nreal 0m2.690s\n$ time python3@3.6.2 -c 'print(6*7)'\n42\nreal 0m0.035sThe first run took 2.7 seconds to fetch the NARs and unpack them, the second run was instantaneous because the store paths were already present.
\nOther than that? Not really, which is pretty amazing.
\nFor any long-lived machine, you would expect your /nix/store to already be warmed up with the packages you need, so the first access penalty is not a big deal.
I remember one of the first things that blew my mind and sold me on Nix, was seeing a demo by @burke on comma. The capability to test a package, at a single nixpkgs revision, without “installing it”; revolutionary! I believe this to be a spiritual successor and I hope to imbue others with the same sense of wonder and amazement that I felt back then as a beacon of the power of Nix.
\nThe repo is at github.com/fzakaria/omnibin.
\nPlease ls responsibly.