运行git reset以更新索引条目后，可以使用git-checkout [1]检查索引中的内容到工作树。或者，使用git-checkout [1]并指定提交，您可以一次性将提交中的路径内容复制到索引和工作树。
问：有人能举例说明所引用段落的含义吗？
注意此问题特别要求引用git reset [-q] [<tree-ish>] [--] <paths>…变体的段落。我知道git reset <path>做了什么，但无法理解上面的代码片段
从git reset开始，以获得更好的背景。假设我们在工作树中更改了hello.c，并将其添加到索引中。
$ git status
On branch feature02
Changes to be committed:
(use "git reset HEAD <file>..." to unstage)
modified: hello.c
现在，运行git reset以将索引条目更新回状态，就像我们将其添加到索引之前一样。
$ git reset -- hello.c
Unstaged changes after reset:
M hello.c
$ git status
On branch feature02
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: hello.c
no changes added to commit (use "git add" and/or "git commit -a")
到目前为止，工作树仍然包含我们的最后更改，而索引更新以匹配HEAD。好吧，让我们使用git-checkout [1]检查索引到工作树的内容。请小心，因为此命令会丢失对工作树中hello.c的更改。
$ git checkout -- hello.c
$ git status
On branch feature02
nothing to commit, working tree clean
现在，索引和工作树都会更新以匹配HEAD。所以它说working tree clean。
我们开始时回到原始状态：
$ git status
On branch feature02
Changes to be committed:
(use "git reset HEAD <file>..." to unstage)
modified: hello.c
使用git-checkout [1]并指定提交。
$ git checkout HEAD hello.c
$ git status
On branch feature02
nothing to commit, working tree clean
我们在这里，索引和工作树都被更新以匹配HEAD。这就是为什么我们一气呵成。
这里的一些技巧是git checkout的2种用法：
git checkout -- hello.c
&
git checkout HEAD hello.c
没有命名提交的第一个是从索引（到工作树）复制内容，而后者是从提交历史（到索引和工作树）。
我建议阅读Pro Git的前三章，这将使您更好地理解Git模型，这对理解这一点非常关键。
tl; dr是这个版本的reset只更新索引（即缓存，临时区域）而不触及工作树（你可以看到的文件）或HEAD，如果你这样做，你可以使用checkout带来你的与索引一致的工作树（或者只是使用checkout来执行这两个操作 - 获取特定版本的文件并同时使用它们更新索引和工作树）。
我们以Git存储库为例。首先，我将确定一个特定的提交和一个特定的更改用作示例：
$ git show --stat HEAD
commit e7e07d5a4fcc2a203d9873968ad3e6bd4d7419d7
Author: Junio C Hamano <[email protected]>
Date: Fri Feb 24 10:49:58 2017 -0800
Git 2.12
Signed-off-by: Junio C Hamano <[email protected]>
Documentation/RelNotes/2.12.0.txt | 6 ++++++
Documentation/git.txt | 5 +++++
GIT-VERSION-GEN | 2 +-
3 files changed, 12 insertions(+), 1 deletion(-)
$ git show HEAD -- Documentation/git.txt
commit e7e07d5a4fcc2a203d9873968ad3e6bd4d7419d7
Author: Junio C Hamano <[email protected]>
Date: Fri Feb 24 10:49:58 2017 -0800
Git 2.12
Signed-off-by: Junio C Hamano <[email protected]>
diff --git a/Documentation/git.txt b/Documentation/git.txt
index 4f208fab9..aa895da4a 100644
--- a/Documentation/git.txt
+++ b/Documentation/git.txt
@@ -44,6 +44,11 @@ unreleased) version of Git, that is available from the 'master'
branch of the `git.git` repository.
Documentation for older releases are available here:
+* link:v2.12.0/git.html[documentation for release 2.12.0]
+
+* release notes for
+ link:RelNotes/2.12.0.txt[2.12].
+
* link:v2.11.1/git.html[documentation for release 2.11.1]
* release notes for
现在让我们使用你所谈论的形式，git reset [tree-ish] [--] [paths]：
$ git reset HEAD^ -- Documentation/git.txt
Unstaged changes after reset:
M Documentation/git.txt
$ git status
On branch master
Your branch is up-to-date with 'origin/master'.
Changes to be committed:
(use "git reset HEAD <file>..." to unstage)
modified: Documentation/git.txt
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: Documentation/git.txt
我们可以检查索引状态和HEAD之间的差异如下：
$ git diff --staged
diff --git a/Documentation/git.txt b/Documentation/git.txt
index aa895da4a..4f208fab9 100644
--- a/Documentation/git.txt
+++ b/Documentation/git.txt
@@ -44,11 +44,6 @@ unreleased) version of Git, that is available from the 'master'
branch of the `git.git` repository.
Documentation for older releases are available here:
-* link:v2.12.0/git.html[documentation for release 2.12.0]
-
-* release notes for
- link:RelNotes/2.12.0.txt[2.12].
-
* link:v2.11.1/git.html[documentation for release 2.11.1]
* release notes for
请注意，这与HEAD提交完全相反：我们索引中的Documentation/git.txt版本与HEAD^中记录的版本匹配。我们还可以将我们的工作树与HEAD进行比较：
$ git diff HEAD
# no output, because there's no difference
我们还可以将工作树与索引进行比较：
$ git diff
diff --git a/Documentation/git.txt b/Documentation/git.txt
index 4f208fab9..aa895da4a 100644
--- a/Documentation/git.txt
+++ b/Documentation/git.txt
@@ -44,6 +44,11 @@ unreleased) version of Git, that is available from the 'master'
branch of the `git.git` repository.
Documentation for older releases are available here:
+* link:v2.12.0/git.html[documentation for release 2.12.0]
+
+* release notes for
+ link:RelNotes/2.12.0.txt[2.12].
+
* link:v2.11.1/git.html[documentation for release 2.11.1]
* release notes for
碰巧模仿HEAD中的提交，因为我们的索引对应HEAD^但我们的工作树仍然与HEAD对齐！ （这部分特别令人困惑，但是一旦你知道它是如何工作它会更有意义。）如果我们checkout（因此将索引中的版本复制到工作树），这将不再是这种情况：
$ git checkout -- Documentation/git.txt
$ git status
On branch master
Your branch is up-to-date with 'origin/master'.
Changes to be committed:
(use "git reset HEAD <file>..." to unstage)
modified: Documentation/git.txt
我们看到我们的工作树现在与索引匹配，实际上HEAD和工作树之间的差异与HEAD和索引之间的前一个差异对齐：
$ git diff HEAD
diff --git a/Documentation/git.txt b/Documentation/git.txt
index aa895da4a..4f208fab9 100644
--- a/Documentation/git.txt
+++ b/Documentation/git.txt
@@ -44,11 +44,6 @@ unreleased) version of Git, that is available from the 'master'
branch of the `git.git` repository.
Documentation for older releases are available here:
-* link:v2.12.0/git.html[documentation for release 2.12.0]
-
-* release notes for
- link:RelNotes/2.12.0.txt[2.12].
-
* link:v2.11.1/git.html[documentation for release 2.11.1]
* release notes for
这种组合（git reset HEAD^ -- Documentation/git.txt && git checkout -- Documentation/git.txt）相当于git checkout HEAD^ -- Documentation/git.txt。