error: Your local changes to the following files would be overwritten by merge:
       
Please commit your changes or stash them before you merge.

$ git stash     //暂存当前正在进行的工作。
$ git pull   origin master //拉取服务器的代码
$ git stash pop //合并暂存的代码

$git reset --hard  //回滚到上一个版本
$git pull origin master