wtf is nix-airgapped-copy?

The nix-airgapped-copy project solves a very specific but important problem: it helps you move software built with the Nix package manager onto a computer that has no internet connection. The README notes that this version is archived, with development moved to a related project called flakegap, but the core idea remains the same. The tool works in two main steps: export and import. First, on a computer with internet access, you run a command that bundles up all the software packages, dependencies, and project files you need into a single portable archive. Then, you physically move that archive to your offline computer. On the disconnected machine, you run an import command that unpacks everything and builds your project, all without needing to contact any online servers. This would be useful for teams working in high-security environments, such as government, defense, or financial systems, where computers are deliberately kept offline to prevent data leaks or malware infections. If you are a developer who needs to run or update software on one of these isolated machines, this tool lets you prepare everything on a connected laptop and transfer it via a USB drive or similar method. The project uses Docker containers to keep the process consistent and reproducible. During the import step, the tool deliberately runs with network access disabled, which proves that the build truly works without any internet connection. This design choice acts as a built-in safety check: if anything was missed during the export step, the build will simply fail rather than silently reaching out to the web for missing pieces.