{
  # Exposes a formatter output and a check that uses the same formatter on
  # a file in this example directory.
  description = "A minimal formatter and checks example";

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

  outputs =
    { nixpkgs, ... }:
    let
      system = "x86_64-linux";
      pkgs = import nixpkgs { inherit system; };
    in
    {
      formatter.${system} = pkgs.nixfmt;

      checks.${system}.formats = pkgs.runCommand "formatter-check" { } ''
        cp ${./sample.nix} ./sample.nix
        ${pkgs.nixfmt}/bin/nixfmt ./sample.nix >/dev/null
        grep -q 'greeting = "hello";' ./sample.nix
        echo ok > "$out"
      '';
    };
}