sudo cp /etc/apt/sources.list /etc/apt/sources.list.backup
sudo vim /etc/apt/sources.list
1 deb http://mirrors.aliyun.com/ubuntu/ focal main restricted 2 deb http://mirrors.aliyun.com/ubuntu/ focal-updates main restricted 3 deb http://mirrors.aliyun.com/ubuntu/ focal universe 4 deb http://mirrors.aliyun.com/ubuntu/ focal-updates universe 5 deb http://mirrors.aliyun.com/ubuntu/ focal multiverse 6 deb http://mirrors.aliyun.com/ubuntu/ focal-updates multiverse 7 deb http://mirrors.aliyun.com/ubuntu/ focal-backports main restricted universe multiverse 8 deb http://mirrors.aliyun.com/ubuntu/ focal-security main restricted 9 deb http://mirrors.aliyun.com/ubuntu/ focal-security universe 10 deb http://mirrors.aliyun.com/ubuntu/ focal-security multiverse
sudo apt-get update
sudo apt-get upgrade
原文：https://www.cnblogs.com/zengcan/p/14811323.html