echo -e "deb http://mirrors.ustc.edu.cn/raspbian/raspbian/ stretch main
contrib non-free rpi \n deb-src http://mirrors.ustc.edu.cn/raspbian/raspbian/
stretch main contrib non-free rpi" > /etc/apt/sources.list
echo -e "deb http://mirrors.ustc.edu.cn/archive.raspberrypi.org/ stretch main
ui" > /etc/apt/sources.list.d/raspi.list
exit