| I updated a comment I wrote earlier about what nix is. Always remember to keep your mind and body pure (I kid, but purity is a common theme in nix). Nix is a programming language plus utilities. It is designed for packaging software in a reproducible way (https://github.com/nixos/nix/). Each package is called a "derivation", which is a function that takes inputs and makes output. The inputs are everything that is needed to make the output. It is "pure functional" package management - for the same input arguments, the same output will be produced. Nix is really fast because each derivation is hashed and cached and the language is lazy-evaluated. Builds are "hermetic", meaning only the inputs specified in the derivation are available at build time. Contrast this to some packaging systems, where the build is done against some staging area where packages get installed as they are built and the output can depend on the non-deterministic order that packages are built. Nixpkgs (https://github.com/nixos/nixpkgs/) is a large collection of recipes for existing software. It contains both rules to build software as well as "modules" to configure it or extend it. NixOS the linux distribution is also part of nixpkgs. There are lots of design patterns here and it can go pretty deep. There are also tons of hacks and patches and workarounds to make software conform to the way nix works. Nixpkgs also has a lot of useful library modules built in. Nix is the latin word for snow. Nix "flakes" are a way to combine multiple flakes as inputs as well as pin their version. Kind of like pipenv/requirements.txt or "cargo lock" or "yarn lock" but for anything. The output of derivations go in the "nix store" which is a path like /nix/store/<hash>/, so all sorts of software can co-exist (think multiple incompatible versions of the same library) and can be referenced in a fixed way. Any kind of software can be packaged as a ".nix" file. It's really common to make a "shell" for software. For example, today I wanted to run GIMP (the image editor). I didn't have to install it in a traditional sense. Instead, I ran 'nix shell nixpkgs#gimp -c gimp'. That makes a shell environment for the "nixpkgs#gimp" derivation, including adding /nix/store/12naig12mnhrzpn88bvvw2vakyd18sjq-gimp-2.10.34/bin to PATH, and runs a shell script command (gimp). Nix makes sure to fetch all the outputs and runtime dependencies of the gimp package for me (which are cached locally and on the internet). |