工作中经常用到，记录下，首先我们需要备份下原来的源文件
sudo cp /etc/apt/source.list /etc/apt/source.list_bak
然后复制以下内容替换原来的source.list文件内容
清华源
deb https://mirrors.tuna.tsinghua.edu.cn/ubuntu/ eoan main restricted universe multiverse deb-src https://mirrors.tuna.tsinghua.edu.cn/ubuntu/ eoan main restricted universe multiverse deb https://mirrors.tuna.tsinghua.edu.cn/ubuntu/ eoan-updates main restricted universe multiverse deb-src https://mirrors.tuna.tsinghua.edu.cn/ubuntu/ eoan-updates main restricted universe multiverse deb https://mirrors.tuna.tsinghua.edu.cn/ubuntu/ eoan-backports main restricted universe multiverse deb-src https://mirrors.tuna.tsinghua.edu.cn/ubuntu/ eoan-backports main restricted universe multiverse deb https://mirrors.tuna.tsinghua.edu.cn/ubuntu/ eoan-security main restricted universe multiverse deb-src https://mirrors.tuna.tsinghua.edu.cn/ubuntu/ eoan-security main restricted universe multiverse deb https://mirrors.tuna.tsinghua.edu.cn/ubuntu/ eoan-proposed main restricted universe multiverse deb-src https://mirrors.tuna.tsinghua.edu.cn/ubuntu/ eoan-proposed main restricted universe multiverse
阿里源
deb http://mirrors.aliyun.com/ubuntu/ focal main restricted universe multiverse deb-src http://mirrors.aliyun.com/ubuntu/ focal main restricted universe multiverse deb http://mirrors.aliyun.com/ubuntu/ focal-security main restricted universe multiverse deb-src http://mirrors.aliyun.com/ubuntu/ focal-security main restricted universe multiverse deb http://mirrors.aliyun.com/ubuntu/ focal-updates main restricted universe multiverse deb-src http://mirrors.aliyun.com/ubuntu/ focal-updates main restricted universe multiverse deb http://mirrors.aliyun.com/ubuntu/ focal-proposed main restricted universe multiverse deb-src http://mirrors.aliyun.com/ubuntu/ focal-proposed main restricted universe multiverse deb http://mirrors.aliyun.com/ubuntu/ focal-backports main restricted universe multiverse deb-src http://mirrors.aliyun.com/ubuntu/ focal-backports main restricted universe multiverse
163源
deb http://mirrors.163.com/ubuntu/ focal main restricted universe multiverse deb http://mirrors.163.com/ubuntu/ focal-security main restricted universe multiverse deb http://mirrors.163.com/ubuntu/ focal-updates main restricted universe multiverse deb http://mirrors.163.com/ubuntu/ focal-proposed main restricted universe multiverse deb http://mirrors.163.com/ubuntu/ focal-backports main restricted universe multiverse deb-src http://mirrors.163.com/ubuntu/ focal main restricted universe multiverse deb-src http://mirrors.163.com/ubuntu/ focal-security main restricted universe multiverse deb-src http://mirrors.163.com/ubuntu/ focal-updates main restricted universe multiverse deb-src http://mirrors.163.com/ubuntu/ focal-proposed main restricted universe multiverse deb-src http://mirrors.163.com/ubuntu/ focal-backports main restricted universe multiverse
然后更新源即可
sudo apt-get update