Nix description

See also

• https://github.com/NixOS/nix

• https://nixos.org/nix/

• https://github.com/NixOS/nixpkgs

• https://github.com/NixOS/nixos-weekly

• https://github.com/NixOS/nixos-weekly/pulls

Description

Nix is a purely functional package manager.

This means that it treats packages like values in purely functional programming languages such as Haskell — they are built by functions that don’t have side-effects, and they never change after they have been built.

Nix stores packages in the Nix store, usually the directory /nix/store, where each package has its own unique subdirectory such as

/nix/store/b6gvzjyb2pg0kjfwrjmg1vfhh54ad73z-firefox-33.1/

where b6gvzjyb2pg0… is a unique identifier for the package that captures all its dependencies (it’s a cryptographic hash of the package’s build dependency graph).

This enables many powerful features.

Multiple versions

You can have multiple versions or variants of a package installed at the same time. This is especially important when different applications have dependencies on different versions of the same package — it prevents the DLL hell

Because of the hashing scheme, different versions of a package end up in different paths in the Nix store, so they don’t interfere with each other.

An important consequence is that operations like upgrading or uninstalling an application cannot break other applications , since these operations never destructively update or delete files that are used by other packages.