1.先备份原有的源

sudo cp /etc/apt/source.list /etc/apt/source.list.bak 
 
sudo vi /etc/apt/source.list  

打开后，按“100dd”，再按“i”。

2.复制换源

搜狐源

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

网易源

deb http://mirrors.163.com/ubuntu/ trusty main restricted universe multiverse  
  
deb http://mirrors.163.com/ubuntu/ trusty-security main restricted universe multiverse  
  
deb http://mirrors.163.com/ubuntu/ trusty-updates main restricted universe multiverse  
  
deb http://mirrors.163.com/ubuntu/ trusty-proposed main restricted universe multiverse  
  
deb http://mirrors.163.com/ubuntu/ trusty-backports main restricted universe multiverse  
  
deb-src http://mirrors.163.com/ubuntu/ trusty main restricted universe multiverse  
  
deb-src http://mirrors.163.com/ubuntu/ trusty-security main restricted universe multiverse  
  
deb-src http://mirrors.163.com/ubuntu/ trusty-updates main restricted universe multiverse  
  
deb-src http://mirrors.163.com/ubuntu/ trusty-proposed main restricted universe multiverse  
  
deb-src http://mirrors.163.com/ubuntu/ trusty-backports main restricted universe multiverse

阿里云源

deb-src http://archive.ubuntu.com/ubuntu xenial main restricted #Added by software-properties  

deb http://mirrors.aliyun.com/ubuntu/ xenial main restricted  

deb-src http://mirrors.aliyun.com/ubuntu/ xenial main restricted multiverse universe 

deb http://mirrors.aliyun.com/ubuntu/ xenial-updates main restricted  

deb-src http://mirrors.aliyun.com/ubuntu/ xenial-updates main restricted multiverse universe #Added by software-properties  

deb http://mirrors.aliyun.com/ubuntu/ xenial universe  

deb http://mirrors.aliyun.com/ubuntu/ xenial-updates universe  

deb http://mirrors.aliyun.com/ubuntu/ xenial multiverse  

deb http://mirrors.aliyun.com/ubuntu/ xenial-updates multiverse  

deb http://mirrors.aliyun.com/ubuntu/ xenial-backports main restricted universe multiverse  

deb-src http://mirrors.aliyun.com/ubuntu/ xenial-backports main restricted universe multiverse #Added by software-properties  

deb http://archive.canonical.com/ubuntu xenial partner  

deb-src http://archive.canonical.com/ubuntu xenial partner  

deb http://mirrors.aliyun.com/ubuntu/ xenial-security main restricted 
 
deb-src http://mirrors.aliyun.com/ubuntu/ xenial-security main restricted multiverse universe #Added by software-properties  

deb http://mirrors.aliyun.com/ubuntu/ xenial-security universe 
 
deb http://mirrors.aliyun.com/ubuntu/ xenial-security multiverse  

！！！复制粘贴后，记得保存。按“Esc”，再按“wq!”。

3.执行命令进行源更新

sudo apt-get update

sudo apt-get upgrade

sudo apt-get dist-upgrade