erlang执行shell

cmd(Command) -> string()
Types:
Command = atom() | io_lib:chars()

open_port(PortName, PortSettings) -> port()
Types:
PortName = 
    {spawn, Command :: string() | binary()} |
    {spawn_driver, Command :: string() | binary()} |
    {spawn_executable, FileName :: file:name()} |
    {fd, In :: integer() >= 0, Out :: integer() >= 0}
PortSettings = [Opt]
Opt = 
    {packet, N :: 1 | 2 | 4} |
    stream |
    {line, L :: integer() >= 0} |
    {cd, Dir :: string() | binary()} |
    {env, Env :: [{Name :: string(), Val :: string() | false}]} |
    {args, [string() | binary()]} |
    {arg0, string() | binary()} |
    exit_status |
    use_stdio |
    nouse_stdio |
    stderr_to_stdout |
    in |
    out |
    binary |
    eof |
    {parallelism, Boolean :: boolean()} |
    hide

loop2() ->
    receive
        {build} ->
            io:format("build ...~n"),
            Port = open_port({spawn_executable, "path/build_ios_nolog.sh"}, [stream, exit_status, eof, hide]),
            Result = get_data(Port, []),
            io:format("~p~n", [Result]),
            loop2();
        stop ->
            ok;
        _ ->
            io:format("recv unknown message!~n"),
            loop2()
    end.

get_data(Port, Sofar) ->
    receive
        {Port, {data, Bytes}} ->
            get_data(Port, [Sofar|Bytes]);
        {Port, eof} ->
            Port ! {self(), close},
            receive
                {Port, closed} -> true
            end,
            receive
                {'EXIT',  Port,  _} -> ok
            after 1 -> ok
            end,
            ExitCode =
            receive
                {Port, {exit_status, Code}} -> Code
            end,
            {ExitCode, lists:flatten(Sofar)}
            %{ExitCode, Sofar}
    end.