換成國內最快的阿裏雲源

第一步：備份原來的源文件

cd /etc/apt/  

然後會顯示下面的源文件sources.list
輸入命令
sudo cp sources.list sources.list.bak
就是將sources.list備份到sources.list.bak

第二步：替換源

阿裏雲源的文件

    deb http://mirrors.aliyun.com/ubuntu/ xenial main restricted universe multiverse  
    deb http://mirrors.aliyun.com/ubuntu/ xenial-security main restricted universe multiverse  
    deb http://mirrors.aliyun.com/ubuntu/ xenial-updates main restricted universe multiverse  
    deb http://mirrors.aliyun.com/ubuntu/ xenial-backports main restricted universe multiverse  
    ##測試版源  
    deb http://mirrors.aliyun.com/ubuntu/ xenial-proposed main restricted universe multiverse  
    # 源碼  
    deb-src http://mirrors.aliyun.com/ubuntu/ xenial main restricted universe multiverse  
    deb-src http://mirrors.aliyun.com/ubuntu/ xenial-security main restricted universe multiverse  
    deb-src http://mirrors.aliyun.com/ubuntu/ xenial-updates main restricted universe multiverse  
    deb-src http://mirrors.aliyun.com/ubuntu/ xenial-backports main restricted universe multiverse  
    ##測試版源  
    deb-src http://mirrors.aliyun.com/ubuntu/ xenial-proposed main restricted universe multiverse  
    # Canonical 合作夥伴和附加  
    deb http://archive.canonical.com/ubuntu/ xenial partner  
    deb http://extras.ubuntu.com/ubuntu/ xenial main  
 

替換並保存
sudo gedit sources.list打開文件，替換成阿裏雲文件即可

第三步：更新源和軟件

   sudo apt-get update 更新源  
   sudo apt-get upgrade 更新軟件 

ubuntu配置阿裏雲源