Ubuntu20.04更换国内源

备份原来的源

sudo cp /etc/apt/sources.list /etc/apt/sources.list.bak

更换源

 sudo vim/etc/apt/sources.list

• sources.list

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

更新源

sudo apt-get update

更新软件

sudo apt-get upgrade