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 sound 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 or 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 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 a commit, making it a topic branch
$ git branch topic/wip (1)
$ git reset --hard HEAD~3 (2)
$ git switch 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 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 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 working 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 switch feature ;# you were working in "feature" branch and
$ work work work ;# got interrupted
$ git commit -a -m "snapshot WIP" (1)
$ git switch master
$ fix fix fix
$ git commit ;# commit with real log
$ git switch 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 committed
previously. You can start a new branch and reset it while
keeping the changes in your working tree.
$ git tag start
$ git switch -c branch1
$ edit
$ git commit ... (1)
$ edit
$ git switch -c 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 switch -c branch2
start), but nobody is perfect.
3. But you can use reset --keep to remove the unwanted commit
after you switched to branch2.
Split a commit apart into a sequence of commits
Suppose that you have created lots of logically separate
changes and committed them together. Then, later you decide
that it might be better to have each logical chunk associated
with its own commit. You can use git reset to rewind history
without changing the contents of your local files, and then
successively use git add -p to interactively select which
hunks to include into each commit, using git commit -c to
pre-populate the commit message.
$ git reset -N HEAD^ (1)
$ git add -p (2)
$ git diff --cached (3)
$ git commit -c HEAD@{1} (4)
... (5)
$ git add ... (6)
$ git diff --cached (7)
$ git commit ... (8)
1. First, reset the history back one commit so that we remove
the original commit, but leave the working tree with all the
changes. The -N ensures that any new files added with HEAD
are still marked so that git add -p will find them.
2. Next, we interactively select diff hunks to add using the
git add -p facility. This will ask you about each diff hunk
in sequence and you can use simple commands such as "yes,
include this", "No don't include this" or even the very
powerful "edit" facility.
3. Once satisfied with the hunks you want to include, you
should verify what has been prepared for the first commit by
using git diff --cached. This shows all the changes that have
been moved into the index and are about to be committed.
4. Next, commit the changes stored in the index. The -c
option specifies to pre-populate the commit message from the
original message that you started with in the first commit.
This is helpful to avoid retyping it. The HEAD@{1} is a
special notation for the commit that HEAD used to be at prior
to the original reset commit (1 change ago). See
git-reflog(1) for more details. You may also use any other
valid commit reference.
5. You can repeat steps 2-4 multiple times to break the
original code into any number of commits.
6. Now you've split out many of the changes into their own
commits, and might no longer use the patch mode of git add,
in order to select all remaining uncommitted changes.
7. Once again, check to verify that you've included what you
want to. You may also wish to verify that git diff doesn't
show any remaining changes to be committed later.
8. And finally create the final commit.
