Purely functional package manager (systemd setup)

 A powerful package manager for Linux and other Unix systems that
 makes package management reliable and reproducible. Nix provides
 atomic upgrades and rollbacks, side-by-side installation of multiple
 versions of a package, multi-user package management and easy setup
 of build environments.
 .
 This package uses systemd mechanisms to setup the nix package
 manager.
 .
 NOTE: This package creates (via tmpfiles.d) a top-level folder /nix.
 This is not compliant with the file hierarchy standard but should not
 be a problem for most people. See /usr/share/doc/nix-bin/README.Debian.