如何在Erlang中跨目录复制文件？

-module(copy_file).
-export([copy/2]).

copy(Src, Dst) ->
    case filelib:is_file(Src) of
        true ->
            case filelib:ensure_dir(Dst) of
                ok ->
                    case file:copy(Src, Dst) of
                        {ok, _} ->
                            ok;
                        {error, Reason} ->
                            {error, Reason}
                    end;
                {error, Reason} ->
                    {error, Reason}
            end;
        false ->
            {error, enoent}
    end.

1> c(copy_file).
{ok,copy_file}
2> copy_file:copy("/path/to/source/file.txt", "/path/to/destination/file.txt").
ok