My Pi 3 Install Log (8) - usb tethering to an android phone

On the road, the cellphone data plan is the only way how Pi stays connected.

1. edit this file: /etc/network/interfaces

2. append these lines:
iface usb0 inet dhcp
auto eth0
iface eth0 inet dhcp
iface usb0 inet dhcp

3. save and quit file

4. connect android phone and start
    sudo ifup usb0

5. similarly to stop:
  sudo ifdown usb0

ref:
https://xsatria.workpress.com/2013/07/09/usb-tethering-from-android-to-raspberry-pi