git status
初始状态是，什么都没有修改：
# On branch master
nothing to commit (working directory
修改了一个文件fu ，状态变成
[root@172.18.4.100 gitlearn]# git status
# On branch master
# Changed but not updated:
# (use "git add <file>..." to update what will be committed)
# (use "git checkout -- <file>..." to discard changes in working directory)
#
# modified: fu
#
no changes added to commit (use "git add" and/or "git commit -a")
如果想把这个修改 加入暂存区 ，准备提交 使用 git add
git add fu
执行之后的状态：
[root@172.18.4.100 gitlearn]# git status
# On branch master
# Changes to be committed:
# (use "git reset HEAD <file>..." to unstage)
#
# modified: fu
#
这时候，状态就变成 fu处于 暂存区了， 准备去提交。
但如果这时候，想从暂存区撤销回来 ， 根据提示，用 git reset
git reset HEAD fu
# On branch master
# Changed but not updated:
# (use "git add <file>..." to update what will be committed)
# (use "git checkout -- <file>..." to discard changes in working directory)
#
# modified: fu
#
no changes added to commit (use "git add" and/or "git commit -a")
现在又变成 修改，但还没有放入暂存区， 如果这时候，想近一步回退， 回退到什么都没修改的状态，根据提示
使用 git checkout 命令
git checkout – fu
上面这条命令，显示的问题，会把两个连字符 连在一起， 其实是两个连字符。
回到了一开始
# On branch master
nothing to commit (working directory
