anchor.diff:          mkdir -p "$prefix"
           cd "$prefix"
   
  +        if [ -z "$(type -P git)" ]; then
  +            echo "installing Git..."
  +            nix-env -iA nixos.pkgs.git || nix-env -i git
  +        fi
  +
           # Move any old nixos or nixpkgs directories out of the way.
           backupTimestamp=$(date "+%Y%m%d%H%M%S")
   
  
positive.code: # This module generates the nixos-checkout script, which replaces the
  # NixOS and Nixpkgs source trees in /etc/nixos/{nixos,nixpkgs} with
  # Subversion checkouts.
  
  {config, pkgs, ...}:
  
  
negative.code:         fi
  
          # Check out the NixOS and Nixpkgs sources.
          git clone git://github.com/NixOS/nixos.git nixos
          git clone git://github.com/NixOS/nixpkgs.git nixpkgs
        '';
     };
  
  in
  
  {
    environment.systemPackages = [ nixosCheckout ];
  }
  