git reset

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NAME
git-reset - Reset current HEAD to the specified state

SYNOPSIS
git reset [--mixed | --soft | --hard | --merge | --keep] [-q] [<commit>]
git reset [-q] [<commit>] [--] <paths>...
git reset --patch [<commit>] [--] [<paths>...]

DESCRIPTION
Sets the current head to the specified commit and optionally resets the
index and working tree to match.
将当前的HEAD指向特定的提交，并且可以选择是否更新索引和工作树，以与特定的提交相匹配一致。

This command is useful if you notice some small error in a recent
commit (or set of commits) and want to redo that part without showing
the undo in the history.
如果你在最近的一次（或多次）提交中发现一个错误，想重做那一部分且不需要相关的撤销操作，那么这个命令是有用的。

If you want to undo a commit other than the latest on a branch, git-
revert(1) is your friend.

The second and third forms with paths and/or --patch are used to revert
selected paths in the index from a given commit, without moving HEAD.

OPTIONS
--mixed
Resets the index but not the working tree (i.e., the changed files
are preserved but not marked for commit) and reports what has not
been updated. This is the default action.

重置索引但是不更新工作树（这意味着修改过的文件被保持原状，但没有被标记为待提交）并且报告哪些还没有被更新。这个是默认行为。

--soft
Does not touch the index file nor the working tree at all, but
requires them to be in a good order. This leaves all your changed
files "Changes to be committed", as git status would put it.

一点也不会更新索引文件和工作树，但需要它们处于一个良好的顺序。

这将会导致所有修改过的文件处于“修改待提交”的状态，正如git status所要输出的。

--hard
Matches the working tree and index to that of the tree being
switched to. Any changes to tracked files in the working tree since
<commit> are lost.
更新工作树及索引至特定的提交。工作目录中，此提交之后的对跟踪文件的任何修改都将丢失。

PS: 操作失误的话，只要有早期的commit hash值，还是可以再reset回去的。

--merge
Resets the index to match the tree recorded by the named commit,
and updates the files that are different between the named commit
and the current commit in the working tree.

--keep
Reset the index to the given commit, keeping local changes in the
working tree since the current commit, while updating working tree
files without local changes to what appears in the given commit. If
a file that is different between the current commit and the given
commit has local changes, reset is aborted.

-p, --patch
Interactively select hunks in the difference between the index and
<commit> (defaults to HEAD). The chosen hunks are applied in
reverse to the index.

This means that git reset -p is the opposite of git add -p (see
git-add(1)).

-q, --quiet
Be quiet, only report errors.

<commit>
Commit to make the current HEAD. If not given defaults to HEAD.

DISCUSSION
The tables below show what happens when running:

git reset --option target

to reset the HEAD to another commit (target) with the different reset
options depending on the state of the files.

In these tables, A, B, C and D are some different states of a file. For
example, the first line of the first table means that if a file is in
state A in the working tree, in state B in the index, in state C in
HEAD and in state D in the target, then "git reset --soft target" will
put the file in state A in the working tree, in state B in the index
and in state D in HEAD.

working index HEAD target working index HEAD
----------------------------------------------------
A B C D --soft A B D
--mixed A D D
--hard D D D
--merge (disallowed)
--keep (disallowed)

working index HEAD target working index HEAD
----------------------------------------------------
A B C C --soft A B C
--mixed A C C
--hard C C C
--merge (disallowed)
--keep A C C

working index HEAD target working index HEAD
----------------------------------------------------
B B C D --soft B B D
--mixed B D D
--hard D D D
--merge D D D
--keep (disallowed)

working index HEAD target working index HEAD
----------------------------------------------------
B B C C --soft B B C
--mixed B C C
--hard C C C
--merge C C C
--keep B C C

working index HEAD target working index HEAD
----------------------------------------------------
B C C D --soft B C D
--mixed B D D
--hard D D D
--merge (disallowed)
--keep (disallowed)

working index HEAD target working index HEAD
----------------------------------------------------
B C C C --soft B C C
--mixed B C C
--hard C C C
--merge B C C
--keep B C C

"reset --merge" is meant to be used when resetting out of a conflicted
merge. Any mergy operation guarantees that the work tree file that is
involved in the merge does not have local change wrt the index before
it starts, and that it writes the result out to the work tree. So if we
see some difference between the index and the target and also between
the index and the work tree, then it means that we are not resetting
out from a state that a mergy operation left after failing with a
conflict. That is why we disallow --merge option in this case.

"reset --keep" is meant to be used when removing some of the last
commits in the current branch while keeping changes in the working
tree. If there could be conflicts between the changes in the commit we
want to remove and the changes in the working tree we want to keep, the
reset is disallowed. That’s why it is disallowed if there are both
changes between the working tree and HEAD, and between HEAD and the
target. To be safe, it is also disallowed when there are unmerged
entries.

The following tables show what happens when there are unmerged entries:

working index HEAD target working index HEAD
----------------------------------------------------
X U A B --soft (disallowed)
--mixed X B B
--hard B B B
--merge B B B
--keep (disallowed)

working index HEAD target working index HEAD
----------------------------------------------------
X U A A --soft (disallowed)
--mixed X A A
--hard A A A
--merge A A A
--keep (disallowed)

X means any state and U means an unmerged index.

EXAMPLES
Undo a commit and redo

$ git commit ...
$ git reset --soft HEAD^ (1)
$ edit (2)
$ git commit -a -c ORIG_HEAD (3)

1. This is most often done when you remembered what you just
committed is incomplete, or you misspelled your commit message, or
both. Leaves working tree as it was before "reset".
2. Make corrections to working tree files.
3. "reset" copies the old head to .git/ORIG_HEAD; redo the commit
by starting with its log message. If you do not need to edit the
message further, you can give -C option instead.

See also the --amend option to git-commit(1).

Undo commits permanently

$ git commit ...
$ git reset --hard HEAD~3 (1)

1. The last three commits (HEAD, HEAD^, and HEAD~2) were bad and
you do not want to ever see them again. Do not do this if you have
already given these commits to somebody else. (See the "RECOVERING
FROM UPSTREAM REBASE" section in git-rebase(1) for the implications
of doing so.)

Undo a commit, making it a topic branch

$ git branch topic/wip (1)
$ git reset --hard HEAD~3 (2)
$ git checkout topic/wip (3)

1. You have made some commits, but realize they were premature to
be in the "master" branch. You want to continue polishing them in a
topic branch, so create "topic/wip" branch off of the current HEAD.
2. Rewind the master branch to get rid of those three commits.
3. Switch to "topic/wip" branch and keep working.

Undo add

$ edit (1)
$ git add frotz.c filfre.c
$ mailx (2)
$ git reset (3)
$ git pull git://info.example.com/ nitfol (4)

1. You are happily working on something, and find the changes in
these files are in good order. You do not want to see them when you
run "git diff", because you plan to work on other files and changes
with these files are distracting.
2. Somebody asks you to pull, and the changes sounds worthy of
merging.
3. However, you already dirtied the index (i.e. your index does not
match the HEAD commit). But you know the pull you are going to make
does not affect frotz.c nor filfre.c, so you revert the index
changes for these two files. Your changes in working tree remain
there.
4. Then you can pull and merge, leaving frotz.c and filfre.c
changes still in the working tree.

Undo a merge or pull

$ git pull (1)
Auto-merging nitfol
CONFLICT (content): Merge conflict in nitfol
Automatic merge failed; fix conflicts and then commit the result.
$ git reset --hard (2)
$ git pull . topic/branch (3)
Updating from 41223... to 13134...
Fast-forward
$ git reset --hard ORIG_HEAD (4)

1. Try to update from the upstream resulted in a lot of conflicts;
you were not ready to spend a lot of time merging right now, so you
decide to do that later.
2. "pull" has not made merge commit, so "git reset --hard" which is
a synonym for "git reset --hard HEAD" clears the mess from the
index file and the working tree.
3. Merge a topic branch into the current branch, which resulted in
a fast-forward.
4. But you decided that the topic branch is not ready for public
consumption yet. "pull" or "merge" always leaves the original tip
of the current branch in ORIG_HEAD, so resetting hard to it brings
your index file and the working tree back to that state, and resets
the tip of the branch to that commit.

Undo a merge or pull inside a dirty work tree

$ git pull (1)
Auto-merging nitfol
Merge made by recursive.
nitfol | 20 +++++----
...
$ git reset --merge ORIG_HEAD (2)

1. Even if you may have local modifications in your working tree,
you can safely say "git pull" when you know that the change in the
other branch does not overlap with them.
2. After inspecting the result of the merge, you may find that the
change in the other branch is unsatisfactory. Running "git reset
--hard ORIG_HEAD" will let you go back to where you were, but it
will discard your local changes, which you do not want. "git reset
--merge" keeps your local changes.

Interrupted workflow
Suppose you are interrupted by an urgent fix request while you are
in the middle of a large change. The files in your working tree are
not in any shape to be committed yet, but you need to get to the
other branch for a quick bugfix.

$ git checkout feature ;# you were working in "feature" branch and
$ work work work ;# got interrupted
$ git commit -a -m "snapshot WIP"(1)
$ git checkout master
$ fix fix fix
$ git commit ;# commit with real log
$ git checkout feature
$ git reset --soft HEAD^ ;# go back to WIP state(2)
$ git reset(3)

1. This commit will get blown away so a throw-away log message is
OK.
2. This removes the WIP commit from the commit history, and sets
your working tree to the state just before you made that snapshot.
3. At this point the index file still has all the WIP changes you
committed as snapshot WIP. This updates the index to show your WIP
files as uncommitted.

See also git-stash(1).

Reset a single file in the index
Suppose you have added a file to your index, but later decide you
do not want to add it to your commit. You can remove the file from
the index while keeping your changes with git reset.

$ git reset -- frotz.c (1)
$ git commit -m "Commit files in index" (2)
$ git add frotz.c (3)

1. This removes the file from the index while keeping it in the
working directory.
2. This commits all other changes in the index.
3. Adds the file to the index again.

Keep changes in working tree while discarding some previous commits
Suppose you are working on something and you commit it, and then
you continue working a bit more, but now you think that what you
have in your working tree should be in another branch that has
nothing to do with what you commited previously. You can start a
new branch and reset it while keeping the changes in your work
tree.

$ git tag start
$ git checkout -b branch1
$ edit
$ git commit ... (1)
$ edit
$ git checkout -b branch2 (2)
$ git reset --keep start (3)

1. This commits your first edits in branch1.
2. In the ideal world, you could have realized that the earlier
commit did not belong to the new topic when you created and
switched to branch2 (i.e. "git checkout -b branch2 start"), but
nobody is perfect.
3. But you can use "reset --keep" to remove the unwanted commit
after you switched to "branch2".

AUTHOR
Written by Junio C Hamano <gitster@pobox.com[1]> and Linus Torvalds
<torvalds@osdl.org[2]>

DOCUMENTATION
Documentation by Junio C Hamano and the git-list
<git@vger.kernel.org[3]>.

GIT
Part of the git(1) suite

NOTES
1. gitster@pobox.com
mailto:gitster@pobox.com

2. torvalds@osdl.org
mailto:torvalds@osdl.org

3. git@vger.kernel.org
mailto:git@vger.kernel.org

Git 1.7.1 03/04/2013 GIT-RESET(1)