树莓派换源

sudo -s
echo -e "deb http://mirrors.ustc.edu.cn/raspbian/raspbian/ jessie main non-free contrib \n deb-src http://mirrors.ustc.edu.cn/raspbian/raspbian/ jessie main non-free contrib" > /etc/apt/sources.list
echo -e "deb http://mirrors.ustc.edu.cn/archive.raspberrypi.org/ jessie main" > /etc/apt/sources.list.d/raspi.list
exit
sudo apt-get update && sudo apt-get -y upgrade