步骤
1. 备份
sudo cp/etc/apt/sources.list /etc/apt/sources.list.bak
2. 修改
sudo vim/etc/apt/sources.list
3. 镜像源
清华源
deb http://mirrors.tuna.tsinghua.edu.cn/ubuntu/ focal main restricteddeb http://mirrors.tuna.tsinghua.edu.cn/ubuntu/ focal-updates main restricteddeb http://mirrors.tuna.tsinghua.edu.cn/ubuntu/ focal universedeb http://mirrors.tuna.tsinghua.edu.cn/ubuntu/ focal-updates universedeb http://mirrors.tuna.tsinghua.edu.cn/ubuntu/ focal multiversedeb http://mirrors.tuna.tsinghua.edu.cn/ubuntu/ focal-updates multiversedeb http://mirrors.tuna.tsinghua.edu.cn/ubuntu/ focal-backports main restricted universe multiversedeb http://mirrors.tuna.tsinghua.edu.cn/ubuntu/ focal-security main restricteddeb http://mirrors.tuna.tsinghua.edu.cn/ubuntu/ focal-security universedeb http://mirrors.tuna.tsinghua.edu.cn/ubuntu/ focal-security multiverse
阿里云源
deb http://mirrors.aliyun.com/ubuntu/ focal main restricted universe multiversedeb-src http://mirrors.aliyun.com/ubuntu/ focal main restricted universe multiversedeb http://mirrors.aliyun.com/ubuntu/ focal-security main restricted universe multiversedeb-src http://mirrors.aliyun.com/ubuntu/ focal-security main restricted universe multiversedeb http://mirrors.aliyun.com/ubuntu/ focal-updates main restricted universe multiversedeb-src http://mirrors.aliyun.com/ubuntu/ focal-updates main restricted universe multiversedeb http://mirrors.aliyun.com/ubuntu/ focal-proposed main restricted universe multiversedeb-src http://mirrors.aliyun.com/ubuntu/ focal-proposed main restricted universe multiversedeb http://mirrors.aliyun.com/ubuntu/ focal-backports main restricted universe multiversedeb-src http://mirrors.aliyun.com/ubuntu/ focal-backports main restricted universe multiverse
4. 更新源
sudo apt-get update
5. 更新软件
sudo apt-get dist-upgradesudo apt-get upgrade
