备份配置文件
sudo cp /etc/apt/sources.list /etc/apt/sources.list.save
修改配置文件
sudo vi /etc/apt/sources.list
将下面的内容拷贝到sources.list 文件中，注意根据自己的ubuntu版本选择拷贝
#（ubuntu18） deb http://mirrors.aliyun.com/ubuntu/ bionic main restricted universe multiverse deb http://mirrors.aliyun.com/ubuntu/ bionic-security main restricted universe multiverse deb http://mirrors.aliyun.com/ubuntu/ bionic-updates main restricted universe multiverse deb http://mirrors.aliyun.com/ubuntu/ bionic-proposed main restricted universe multiverse deb http://mirrors.aliyun.com/ubuntu/ bionic-backports main restricted universe multiverse deb-src http://mirrors.aliyun.com/ubuntu/ bionic main restricted universe multiverse deb-src http://mirrors.aliyun.com/ubuntu/ bionic-security main restricted universe multiverse deb-src http://mirrors.aliyun.com/ubuntu/ bionic-updates main restricted universe multiverse deb-src http://mirrors.aliyun.com/ubuntu/ bionic-proposed main restricted universe multiverse deb-src http://mirrors.aliyun.com/ubuntu/ bionic-backports main restricted universe multiverse
（ubuntu20） deb http://mirrors.aliyun.com/ubuntu/ focal main restricted universe multiverse deb http://mirrors.aliyun.com/ubuntu/ focal-security main restricted universe multiverse deb http://mirrors.aliyun.com/ubuntu/ focal-updates main restricted universe multiverse deb 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 main restricted universe multiverse deb-src http://mirrors.aliyun.com/ubuntu/ focal-security main restricted universe multiverse deb-src http://mirrors.aliyun.com/ubuntu/ focal-updates main restricted universe multiverse deb-src http://mirrors.aliyun.com/ubuntu/ focal-proposed main restricted universe multiverse deb-src http://mirrors.aliyun.com/ubuntu/ focal-backports main restricted universe multiverse
编辑好配置文件后，退出vim，在终端运行命令更新源和更新依赖
sudo apt-get update && sudo apt-get upgrade
