let
   nixpkgs = fetchTarball "https://github.com/NixOS/nixpkgs/tarball/nixos-24.05";
   pkgs = import nixpkgs { config = {}; overlays = []; };
 in

 pkgs.mkShellNoCC {
   packages = with pkgs; [
     tldr
     cowsay
     lolcat
     neovim
     fish
     git
     tmux
   ];

   GREETING = "Hello, Nix!";

   shellHook = ''
     fish
   '';
 }