gistfile1.erl

%% Recursively copy directories
-spec recursive_copy(list(), list()) -> ok.                            
recursive_copy(From, To) ->
    {ok, Files} = file:list_dir(From),
    [ok = rec_copy(From, To, X) || X <- Files],
    ok.
 
-spec rec_copy(list(), list(), list()) -> ok.                            
rec_copy(_From, _To, [$. | _T]) -> %% Ignore Hidden
    ok; 
rec_copy(From, To, File) ->
 
    NewFrom = filename:join(From, File),
    NewTo   = filename:join(To, File),
 
    case filelib:is_dir(NewFrom) of
 
        true  ->
            ok = filelib:ensure_dir(NewTo),
            recursive_copy(NewFrom, NewTo);
        
        false ->
            case filelib:is_file(NewFrom) of                
                true  ->
                    ok = filelib:ensure_dir(NewTo),
                    {ok, FileInfo} = file:read_file_info(NewFrom),
                    {ok, _} = file:copy(NewFrom, NewTo),
                    ok = file:write_file_info(NewTo, FileInfo);
                false ->
                    ok            
            end
    end.

This fork preserves file permissions.