廖雪峰Git教程笔记（八）撤销修改

假设，假设，不过现在是凌晨两点，你正在赶一份工作报告，你在readme.txt中添加了一行：

Git is a distributed version control system.
Git is free software distributed under the GPL.
Git has a mutable index called stage.
Git tracks changes of files.
My stupid boss still prefers SVN.

还好没有提交，现在，看一下status和diff

git status
On branch master
Changes not staged for commit:
(use "git add <file>..." to update what will be committed)
(use "git checkout -- <file>..." to discard changes in working directory)

modified:   readme

no changes added to commit (use "git add" and/or "git commit -a")

git diff readme
diff --git a/readme b/readme
index a9c5755..533f857 100644
--- a/readme
+++ b/readme
@@ -2,3 +2,4 @@ Git is a distributed version control system.
Git is free software distributed under the GPL.
Git has a mutable index called stage.
Git tracks changes of files.
+My stupid boss still prefers SVN.

从status看出，git checkout – file可以丢弃工作区修改

git checkout -- readme

这里git checkout – readme意思是，把readme文件在工作区的修改全部撤销，有两种情况：

一种是readme自修改后还没有被放到暂存区，现在，撤销修改就回到和版本库一模一样的状态。

一种是readme已经添加到暂存区后，又做了修改，现在，撤销修改就回到添加到暂存区后的状态

总之，就是让这个文件回到最近一次git commit 或git add时的状态。

现在内容已经恢复了。。。

现在假定是凌晨3点，你不但写了一些胡话，还git add到暂存区了：

Git is a distributed version control system.
Git is free software distributed under the GPL.
Git has a mutable index called stage.
Git tracks changes of files.
My stupid boss still prefers SVN.

git add readme 

查看一下状态

git status readme
On branch master
Changes to be committed:
(use "git reset HEAD <file>..." to unstage)

modified:   readme

从暂存区中撤销

git reset HEAD readme
Unstaged changes after reset:
M   readme

再从工作区中撤销

git checkout -- readme

完成。。。。

小结：使用reset HEAD file可以从暂存区中撤销，使用git checkout – file 可以从工作区中撤销