vi /etc/apt/sources.list
deb 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.debian.org/debian/ stretch main non-free contrib
deb-src http://archive.debian.org/debian/ stretch-backports main non-free contrib
deb http://archive.debian.org/debian-security/ stretch/updates main non-free contrib
deb-src http://archive.debian.org/debian-security/ stretch/updates main non-free contrib
