[$] A look at Nix and Guix
Nix and Guix are a pair of unusual package managers based on the idea of declarative configurations. Their associated Linux distributions — NixOS and the Guix System — take the idea further by allowing users to define a single centralized configuration describing the state of the entire system. Both have been previously mentioned on LWN, but not covered extensively. They offer different takes on the central idea of treating packages like immutable values.