vi /etc/apt/sources.listdeb http://archive.debian.org/debian/ stretch main non-free contrib
deb http://archive.debian.org/debian/ stretch-backports main non-free contrib
deb-src http://archive.debi...
换源vi /etc/apt/sources.listdeb https://mirrors.ustc.edu.cn/debian stretch main contrib non-free
deb https://mirrors.ustc.edu.cn/debian stretch-updates main contrib non-free
deb https://mirrors.ustc....