clone 代码到本地：

 git clone git链接

显示有变更的文件：git stutas

# Clever @ clever in~/Downloads/common on git:master o [11:33:05]

$ git status

On branch master

Your branch isup-to-date with 'origin/master'.

nothing to commit,working tree clean

Git checkout {分支名}:切换到dev分支

# Clever @ clever in~/Downloads/common on git:master o [11:33:16]

$ git checkout dev

Branch dev set up totrack remote branch dev from origin.

Switched to a newbranch 'dev'

Git pull

取回远程主机某个分支的更新，再与本地的指定分支合并

index暂存区