Nix develop example

flake.nix

# Run me:
#  ❯ nix develop .#work -c mysql --version
# mysql  Ver 15.1 Distrib 10.11.6-MariaDB, for Linux (x86_64) using readline 5.1
#  ❯ nix develop .#fun -c vault --version
# Vault v1.15.6 (615cf6f1dce9aa91bc2035ce33b9f689952218f0), built 2024-02-28T17:07:34Z

{
  inputs = {
    nixpkgs.url = "github:NixOS/nixpkgs/nixos-23.11";
    flake-utils.url = "github:numtide/flake-utils";
  };
  outputs = { self, nixpkgs, flake-utils }:
    let
      makeOpinionatedNixpkgs = system: overlays:
        import nixpkgs {
          inherit system;
          config.allowUnfree = true;
          overlays = overlays;
        };
    in
    {
      overlays = {
        wrk = final: prev: {
          vault = prev.vault-bin;
        };
      };
    } //
    flake-utils.lib.eachSystem [ "x86_64-linux" "aarch64-linux" ] (system:
      let
        pkgs = makeOpinionatedNixpkgs system [ self.overlays.wrk ];
      in
      {
        devShells = {
          work = pkgs.mkShell {
            buildInputs = [ pkgs.mysql ];
          };
          fun = pkgs.mkShell {
            buildInputs = [ pkgs.vault ];
          };
        };
      }
    );
}