erlang shell ls

c.erl

ls(Dir) ->
    case file:list_dir(Dir) of
	{ok, Entries} ->
	    ls_print(sort(Entries));
	{error, enotdir} ->
	    ls_print([Dir]);
	{error, Error} ->
	    format("~ts\n", [file:format_error(Error)])
    end.

ls_print([]) -> ok;
ls_print(L) ->
    Cols = columns(),
    Width = min([Cols, max(lengths(L)) + 5]),
    ls_print(L, Cols, Width, 0).

ls_print(X, Cols, Width, Len) when Width + Len > Cols ->
    io:nl(),
    ls_print(X, Cols, Width, 0);
ls_print([H|T], Cols, Width, 0) when Cols div Width =< 1 ->
    io:format("~ts", [H]),
    io:nl(),
    ls_print(T, Cols, Width, 0);
ls_print([H|T], Cols, Width, Len) ->
    io:format("~-*ts", [Width, H]),
    ls_print(T, Cols, Width, Width + Len);
ls_print([], _, _, _) ->
    ok.

lengths(X) ->
    lengths(X, []).
lengths([H|T], L) -> lengths(T, [length(H)|L]);
lengths([], L)    -> L.

columns() ->
    case io:columns() of
    {ok, Cols} ->
        Cols;
    {error, _} ->
        80
    end.

rates ok