an interactive programming guide dedicated to the nix programming language. there is also a standalone version called 'nix-tour' which is based on 'electron' and can be installed and used offline.
'A tour of Nix' focuses on programming language constructs and how Nix can be algorithmically used to solve problems. However, this is not an introduction into nix-env, nix-shell, nix-repl and we won't build/install software using stdenv.mkDerivation. Still we bundled nixpkgs into 'A tour of Nix' and you can use the Nix library functions' from pkgs/lib, which are used for packaging software.