Why does a Nix store path survive garbage collection?
GC Roots, the fifth free Part of LabCraft's Nix course, is now available. On a real NixOS machine, it asks you to predict what garbage collection will remove before Nix shows you what it kept.
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RSSNotes from the lab.
Field notes on systems, judgment, and the infrastructure behind hands-on learning. Long-form, occasionally opinionated, and — like everything we ship — tested against real environments.
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Why is a Nix rollback just a symlink flip?
Profiles and Generations, the fourth free Part of LabCraft's Nix course, is now available. Remove a tool, restore it by switching generations, and prove why wiping history still leaves its store path on disk.
Why does shipping a Nix upgrade move only the difference?
Closures, the third Part of LabCraft's Nix course, is now available. On a real NixOS machine, it asks you to predict what an upgrade will actually move before Nix shows you the answer.
MITM is a feature
On the open internet, terminating someone's TLS in the middle is an attack. Inside a trust domain we own end to end, it is what keeps a real Nix install command from failing because an upstream had a bad day.
What does the hash in a Nix store path actually name?
Store Paths, the second Part of LabCraft's Nix course, is now available. It uses a real NixOS machine to answer what names a path and why that name moves.
nix Didn't Hang. It Was Evaluating the World!
A beginner's first nix search looked like a tiny lookup and behaved like a memory benchmark. We pinned the installer, pinned nixpkgs, and baked the eval cache so the lesson could start with Nix, not the OOM killer.
Learn Nix on a real Linux VM: LabCraft is open in public beta
LabCraft is free during the public beta. Start the Nix course in your browser, work on a real machine, and learn by fixing the failures Nix beginners commonly hit.
Introducing LabCraft: learn Nix where it breaks
Learn Nix on a real VM that's yours to break, with chapters built around the failures everyone hits and checks that inspect what actually ran on the box.
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