linux 切换apt源，以阿里云为例

阿里云源

vi /etc/apt/sources.list

deb http://mirrors.aliyun.com/debian/ buster main contrib non-free
deb-src http://mirrors.aliyun.com/debian/ buster main contrib non-free
 
deb http://mirrors.aliyun.com/debian-security/ buster/updates main contrib non-free
deb-src http://mirrors.aliyun.com/debian-security/ buster/updates main contrib non-free
 
deb http://mirrors.aliyun.com/debian/ buster-updates main contrib non-free
deb-src http://mirrors.aliyun.com/debian/ buster-updates main contrib non-free
 
deb http://mirrors.aliyun.com/debian/ buster-backports main contrib non-free
deb-src http://mirrors.aliyun.com/debian/ buster-backports main contrib non-free