Ubuntu安装vim

一开始直接安装vim：

sudo apt-get install vim

提示失败

Reading package lists... Done
Building dependency tree       
Reading state information... Done
Package vim is not available, but is referred to by another package.
This may mean that the package is missing, has been obsoleted, or
is only available from another source
E: Package vim has no installation candidate

google后使用如下指令：

sudo apt-get update && sudo apt-get install vim

下载安装N个数据包，成功。

原文出处：
http://askubuntu.com/questions/78406/cannot-install-vim

我的系统 - ubuntu12.04