module U = UnixLabels

let f () =
  let (_, pipe_w_1) = U.pipe () in
  let (pipe_r_2, _) = U.pipe () in
  let (pipe_r_3, _) = U.pipe () in
  let _ = U.create_process
      ~prog:"r2"
      ~args:[|"r2"; "-q0"; "/bin/ls"|]
      ~stdin:pipe_w_1
      ~stdout:pipe_r_2
      ~stderr:pipe_r_3
  in
  let cmd = "/j chown" in
  U.write pipe_w_1 ~buf:cmd ~pos:0 ~len:(String.length cmd) |> ignore;
  let buf = Bytes.create 10 in
  (try
    U.read pipe_r_2 ~buf ~pos:0 ~len:10 |> ignore;
  with _ ->
    ());
  print_endline buf