exec shell failed

[shishui]

android 4.4 os app code run shell order:

Process p = Runtime.getRuntime().exec("/system/bin/sh");
OutputStream os = p.getOutputStream();
DataOutputStream dos = new DataOutputStream(os);
dos.writeBytes("system/bin/ifconfig usb0 down");
dos.writeBytes("exit\n");
dos.flush();
dos.close();

The network card usb0 is not closed. has not Exception.

at shell commande line is successed.

please what's the reason.

[jimmychan]

which i.MX chip are you using?

which board are you using?

Android 4.4 is too old. I would suggest you to use the latest BSP.

[shishui]

i.mx chip :im6q.

board ：sabresd_6dq .

Android 4.4 has no official maintenance yet.