——soft:告诉Git将HEAD重置为另一个提交，这样索引和工作目录将不会以任何方式改变。在原始HEAD和提交之间更改的所有文件都将被暂存。

-mixed:就像软的，这将重置HEAD到另一个提交。它还将重置索引以匹配它，而工作目录将不会被触及。所有更改都将保留在工作目录中，并显示为已修改，但不是阶段性的。

——hard:这将重置所有内容——它将HEAD重置回另一个提交，重置索引以匹配它，并重置工作目录以匹配它。

-混合和-软之间的主要区别是你的索引是否也被修改。点击这里查看更多信息。

-混合vs -软vs -硬:

--mixed:

   Delete changes from the local repository and staging area.

   It won't touch the working directory.

   Possible to revert back changes by using the following commands.

     - git add

     - git commit

   Working tree won't be clean.

--soft:

    Deleted changes only from the local repository.

    It won't touch the staging area and working directory.

    Possible to revert back changes by using the following command.

     - git commit.

    Working tree won't be clean

--hard:

    Deleted changes from everywhere.

    Not possible to revert changes.

    The working tree will be clean.

注意:如果提交被确认到本地存储库并放弃这些提交，我们可以使用:

 `git reset command`.

但是如果提交被确认到远程存储库，那么不建议使用reset命令，我们必须使用revert命令来丢弃远程提交。

I’m not a git expert and just arrived on this forum to understand it! Thus maybe my explanation is not perfect, sorry for that. I found all the other answer helpful and I will just try to give another perspective. I will modify a bit the question since I guess that it was maybe the intent of the author: “I’m new to git. Before using git, I was renaming my files like this: main.c, main_1.c, main_2.c when i was performing majors changes in order to be able to go back in case of trouble. Thus, if I decided to come back to main_1.c, it was easy and I also keep main_2.c and main_3.c since I could also need them later. How can I easily do the same thing using git?” For my answer, I mainly use the “regret number three” of the great answer of Matt above because I also think that the initial question is about “what do I do if I have regret when using git?”. At the beginning, the situation is like that:

a b c d(主)

第一个要点是创建一个新分支:git分支mynewbranch。然后一个得到:

(master和mynewbranch)

让我们假设现在有人想要回到A(前3次提交)。第二个要点是使用git reset命令——即使人们可以在网上读到这是危险的，也很难。是的，这很危险，但仅适用于未提交的更改。因此，这样做的方法是:

Git重置——commita的硬数字

or

Git复位-硬主~3

那么就得到: A (master) - B - C - D (mynewbranch)

Then, it’s possible to continue working and commit from A (master) but still can get an easy access to the other versions by checking out on the other branch: git checkout mynewbranch. Now, let’s imagine that one forgot to create a new branch before the command git reset --hard. Is the commit B, C, D are lost? No, but there are not stored in any branches. To find them again, one may use the command : git reflog that is consider as “a safety command”( “in case of trouble, keep calm and use git reflog”). This command will list all commits even those that not belong to any branches. Thus, it’s a convenient way to find the commit B, C or D.

以下是对TortoiseGit用户的基本解释:

Git复位-软-混合不动你的文件。

Git重置-实际上很难改变你的文件来匹配你重置的提交。

在TortoiseGit中，索引的概念被GUI隐藏得很好。当你修改一个文件时，你不必运行git add来将更改添加到暂存区域/索引中。当简单地处理现有文件的修改而不改变文件名时，git reset -soft和-mixed是一样的!只有添加新文件或重命名文件时才会注意到不同之处。在这种情况下，如果你运行git reset——mixed，你将不得不从Not Versioned Files列表中重新添加你的文件。

在研究这三个选项之前，我们必须了解三件事。

1） 历史/头部

2)阶段/索引

3)工作目录

reset——soft:历史记录已更改，HEAD已更改，工作目录未更改。

reset——mixed:历史记录已更改，HEAD已更改，工作目录已更改。

reset——hard:历史记录更改，HEAD更改，工作目录更改，数据丢失。

使用Git总是安全的——软的。在复杂的需求中应该使用其他选项。

用最简单的话来说:

——soft:取消提交更改，更改是阶段性的(index)。 ——mixed(默认):uncommit + unstage变更，变更留在工作树中。 ——难:uncommit + unstage + delete changes，什么都不剩。