is_shell(Pid) ->
    %% The shell never belongs to any applicition.  To optimize, check
    %% that application:get_application(Pid) yields undefined before
    %% calling this function.
    {group_leader, Leader} = erlang:process_info(Pid, group_leadner),
    case lists:keyfind(shell, 1, group:interfaces(Leader)) of
        {shell, Shell} ->
            case Shell =:= Pid of
                true -> true;
                false ->
                    case erlang:process_info(Shell, dictionary) of
                        {dictionary, Dict} ->
                            proplists:get_value(evaluator, Dict) =:= Pid
                    end
            end
    end.