云服务器ubuntu20.04如何更换国内源

ubuntu20.04更换国内源的方法。
1.打开终端。
2.输入以下命令备份原来的源。
sudo?cp?/etc/apt/sources.list?/etc/apt/sources.list.bak
3.再输入以下命令打开sources.list配置文件更换源。
sudo?vim/etc/apt/sources.list//配置内容如下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?focal
4.再输入命令更新源。
sudo?apt-get?update
5.最后输入命令更新一下软件即可。
sudo?apt-get?upgrade