Ubuntu20 更新yum 源   （阿里雲源）

cd /etc/apt
cp sources.list sources.list.bak.20200622 # 備份原始檔，一定要養成這個習慣，即使該配置檔案可能不再使用。
> sources.list # 清空原檔案內容
vim source.list # 將相關內容拷貝到該檔案進行儲存
apt-get update # 更新

內容如下：

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

其他系統配置阿里雲yum源教程地址如下：

           https://me.jinchuang.org/archives/37.html