[git]git命令行自动补齐

1. 下载Git-completion.bash

github地址：https://github.com/markgandolfo/git-bash-completion.git

2. copy到用户根目录~/

cp git-completion.bash ~/.git-completion.bash

3. 使之生效

source ~/.git-completion.bash

4. 修改~/.profile

增加

source ~/.git-completion.bash