nixpkgs/pkgs-ng/system/user-environment.fix

# Given a system identifier, this function returns a derivation of a
# user environment, i.e., a set of symbolic links to `activated'
# packages.  The resulting package is typically passed to the
# `nix-switch' command in order to actually activate it.

{system}: let {
  # All activated packages.
  pkgs = (import ./all-packages.fix) {system = system};

  # This 
  selectedPkgs =
    [ pkgs.aterm
    ];

  body = derivation { 
    name = "user-environment";
    system = system;
    builder = ./populate-linkdirs.pl;
    dirs = selectedPkgs;
  };
}