{ description = "Flake utils demo"; edition = 201909; inputs.utils = { uri = "github:numtide/flake-utils"; }; outputs = { self, nixpkgs, utils }: utils.lib.eachDefaultSystem (system: let pkgs = nixpkgs.legacyPackages.${system}; in rec { packages.hello = pkgs.hello; defaultPackage = packages.hello; apps.hello = utils.lib.mkApp { drv = packages.hello; }; defaultApp = apps.hello; } ); }