gistfile1.hrl

 lists:foldl(fun(F, Acc) -> 
                        case file:open(F, [read, raw, binary]) of 
                            {ok, Io} -> 
                                file:close(Io), 
                                Acc; 
                            {error, Reason} ->
                                [[{file, F},{error, Reason}]|Acc] 
                        end 
                end, 
                [], 
                filelib:fold_files("data/bitcask", "[0-9]+.bitcask.data", true, fun(F, Acc) -> [F|Acc] end, [])).