Minimal nix flake

gistfile1.txt

{
  description = "minimal nix flake with a default package";

  inputs.nixpkgs.url = "github:nixos/nixpkgs/nixos-unstable";

  outputs = { self, nixpkgs }: {
    # packages.x86_64-linux.default = 
    #   with nixpkgs.legacyPackages.x86_64-linux;
      
    packages.aarch64-darwin.default =
      with nixpkgs.legacyPackages.aarch64-darwin;
      stdenv.mkDerivation {
        pname = "hello";
        version = "1.0";

        buildInputs = [
          # cmake
        ];

        src = null;

        unpackPhase = ''
          true
        '';

        buildPhase = ''
          mkdir -p $out/bin
          echo "echo Hello, World!" > $out/bin/hello
          chmod +x $out/bin/hello
        '';
      };

    # defaultPackage.x86_64-linux = self.packages.x86_64-linux.default;
    defaultPackage.aarch64-darwin = self.packages.aarch64-darwin.default;
  };
}

# nix develop
# nix run