修改Ubuntu源

获取本系统代号

# 获取本系统代号
lsb_release -c
-->Codename:	bionic

1. 备份源文件备份

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

2. 修改源文件

   deb http://mirrors.aliyun.com/ubuntu/ bionic main restricted universe multiverse
   deb-src http://mirrors.aliyun.com/ubuntu/ bionic main restricted universe multiverse
   
   
   deb http://mirrors.aliyun.com/ubuntu/ bionic-security main restricted universe multiverse
   deb-src http://mirrors.aliyun.com/ubuntu/ bionic-security main restricted universe multiverse
   
   
   deb http://mirrors.aliyun.com/ubuntu/ bionic-updates main restricted universe multiverse
   deb-src http://mirrors.aliyun.com/ubuntu/ bionic-updates main restricted universe multiverse
   
   
   deb http://mirrors.aliyun.com/ubuntu/ bionic-backports main restricted universe multiverse
   deb-src http://mirrors.aliyun.com/ubuntu/ bionic-backports main restricted universe multiverse
   
   
   deb http://mirrors.aliyun.com/ubuntu/ bionic-proposed main restricted universe multiverse
   deb-src http://mirrors.aliyun.com/ubuntu/ bionic-proposed main restricted universe multiverse
   

3. 更新源列表和软件包

   sudo apt-get update
   sudo apt-get upgrade