1.首先先备份原文件
mv /etc/apt/sources.list /etc/apt/sources.listbak
2.以Jessie为例, 编辑/etc/apt/sources.list文件, 在文件最前面添加以下条目
deb http://mirrors.163.com/debian/ jessie main non-free contrib
deb http://mirrors.163.com/debian/ jessie-updates main non-free contrib
deb http://mirrors.163.com/debian/ jessie-backports main non-free contrib
deb-src http://mirrors.163.com/debian/ jessie main non-free contrib
deb-src http://mirrors.163.com/debian/ jessie-updates main non-free contrib
deb-src http://mirrors.163.com/debian/ jessie-backports main non-free contrib
deb http://mirrors.163.com/debian-security/ jessie/updates main non-free contrib
deb-src http://mirrors.163.com/debian-security/ jessie/updates main non-free contrib
3.如需换成其他版本只要将jessie换成相应版本号即可,可用sed命令:
```
sed -i "s/jessie/buster/g" /etc/apt/sources.list
```
之后再apt update就OK了