备份
sudo cp /etc/apt/sources.list /etc/apt/sources.list_backup
打开文件
sudo gedit /etc/apt/sources.list
设置
阿里源
deb http://mirrors.aliyun.com/debian/ stretch main non-free contrib deb-src http://mirrors.aliyun.com/debian/ stretch main non-free contrib deb http://mirrors.aliyun.com/debian-security stretch/updates main deb-src http://mirrors.aliyun.com/debian-security stretch/updates main deb http://mirrors.aliyun.com/debian/ stretch-updates main non-free contrib deb-src http://mirrors.aliyun.com/debian/ stretch-updates main non-free contrib deb http://mirrors.aliyun.com/debian/ stretch-backports main non-free contrib deb-src http://mirrors.aliyun.com/debian/ stretch-backports main non-free contrib