ubuntu 修改软件源为阿里源镜像

1、备份原来的sources.list源文件

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

2、修改sources.list文件内容

sudo gedit /etc/apt/sources.list

将所有行删除，粘贴阿里云mirrors官网对应Ubuntu版本镜像地址列表进行替换保存：

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

3、更新源和更新软件

sudo apt-get update #更新源
sudo apt-get upgrade #更新软件