1.輸入該命令按回車鍵拷貝源文件進(jìn)行備份：

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

2.輸入該命令按回車鍵：`vi /etc/apt/sources.list`

3.按`i`進(jìn)入插入模式，將文件內(nèi)容修改為如下內(nèi)容，然后按`ESC`鍵輸入`wq`按回車鍵保存退出vi編輯 

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-proposed main restricted universe multiverse \# 
deb-src http://mirrors.aliyun.com/ubuntu/ bionic-proposed 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

4.輸入該命令按回車鍵更新列表：`apt-get update`