Revert and undo changes

Git provides options for undoing changes at any point in the Git workflow.

The method to use depends on whether the changes are:

Only on your local computer.
Stored remotely on a Git server such as GitLab.com.

Undo local changes

Until you push your changes to a remote repository, changes you make in Git are only in your local development environment.

When you stage a file in Git, you instruct Git to track changes to the file in preparation for a commit. To disregard changes to a file, and not include it in your next commit, unstage the file.

Revert unstaged local changes

To undo local changes that are not yet staged:

Confirm that the file is unstaged (that you did not use git add <file>) by running git status:

git status

Example output:

On branch main
Your branch is up-to-date with 'origin/main'.
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:   <file>
no changes added to commit (use "git add" and/or "git commit -a")

Choose an option and undo your changes:
- To overwrite local changes:
```
git checkout -- <file>
```
- To discard local changes to all files, permanently:
```
git reset --hard
```

Revert staged local changes

You can undo local changes that are already staged. In the following example, a file was added to the staging, but not committed:

Confirm that the file is staged with git status:

git status

Example output:

On branch main
Your branch is up-to-date with 'origin/main'.
Changes to be committed:
  (use "git restore --staged <file>..." to unstage)

  new file:   <file>

Choose an option and undo your changes:
- To unstage the file but keep your changes:
```
git restore --staged <file>
```
- To unstage everything but keep your changes:
```
git reset
```
- To unstage the file to current commit (HEAD):
```
git reset HEAD <file>
```
- To discard everything permanently:
```
git reset --hard
```

Undo local commits

When you commit to your local repository with git commit, Git records your changes. Because you did not push to a remote repository yet, your changes are not public or shared with others. At this point, you can undo your changes.

Revert commits without altering history

You can revert a commit while retaining the commit history.

This example uses five commits A,B,C,D,E, which were committed in order: A-B-C-D-E. The commit you want to undo is B.

Find the commit SHA of the commit you want to revert to. To look through a log of commits, use the command git log.
Choose an option and undo your changes:
- To revert changes introduced by commit B:
```
git revert <commit-B-SHA>
```
- To undo changes on a single file or directory from commit B, but retain them in the staged state:
```
git checkout <commit-B-SHA> <file>
```
- To undo changes on a single file or directory from commit B, but retain them in the unstaged state:
```
git reset <commit-B-SHA> <file>
```

Revert commits and modify history

The following sections document tasks that rewrite Git history. For more information, see Rebase and resolve conflicts.

Delete a specific commit

You can delete a specific commit. For example, if you have commits A-B-C-D and you want to delete commit B.

Rebase the range from current commit D to B:
```
git rebase -i A
```
A list of commits is displayed in your editor.
In front of commit B, replace pick with drop.
Leave the default, pick, for all other commits.
Save and exit the editor.

Edit a specific commit

You can modify a specific commit. For example, if you have commits A-B-C-D and you want to modify something introduced in commit B.

Rebase the range from current commit D to B:
```
git rebase -i A
```
A list of commits is displayed in your editor.
In front of commit B, replace pick with edit.
Leave the default, pick, for all other commits.
Save and exit the editor.
Open the file in your editor, make your edits, and commit the changes:
```
git commit -a
```

Undo multiple commits

If you create multiple commits (A-B-C-D) on your branch, then realize commits C and D are wrong, undo both incorrect commits:

Check out the last correct commit. In this example, B.
```
git checkout <commit-B-SHA>
```
Create a new branch.
```
git checkout -b new-path-of-feature
```

Add, push, and commit your changes.

git add .
git commit -m "Undo commits C and D"
git push --set-upstream origin new-path-of-feature

The commits are now A-B-C-D-E.

Alternatively, cherry-pick that commit into a new merge request.

NOTE: Another solution is to reset to B and commit E. However, this solution results in A-B-E, which clashes with what others have locally. Don't use this solution if your branch is shared.

Recover undone commits

You can recall previous local commits. However, not all previous commits are available, because Git regularly cleans the commits that are unreachable by branches or tags.

To view repository history and track prior commits, run git reflog show. For example:

$ git reflog show

# Example output:
b673187 HEAD@{4}: merge 6e43d5987921bde189640cc1e37661f7f75c9c0b: Merge made by the 'recursive' strategy.
eb37e74 HEAD@{5}: rebase -i (finish): returning to refs/heads/master
eb37e74 HEAD@{6}: rebase -i (pick): Commit C
97436c6 HEAD@{7}: rebase -i (start): checkout 97436c6eec6396c63856c19b6a96372705b08b1b
...
88f1867 HEAD@{12}: commit: Commit D
97436c6 HEAD@{13}: checkout: moving from 97436c6eec6396c63856c19b6a96372705b08b1b to test
97436c6 HEAD@{14}: checkout: moving from master to 97436c6
05cc326 HEAD@{15}: commit: Commit C
6e43d59 HEAD@{16}: commit: Commit B

This output shows the repository history, including:

The commit SHA.
How many HEAD-changing actions ago the commit was made (HEAD@{12} was 12 HEAD-changing actions ago).
The action that was taken, for example: commit, rebase, merge.
A description of the action that changed HEAD.

Undo remote changes

You can undo remote changes on your branch. However, you cannot undo changes on a branch that was merged into your branch. In that case, you must revert the changes on the remote branch.

Revert remote changes without altering history

To undo changes in the remote repository, you can create a new commit with the changes you want to undo. This process preserves the history and provides a clear timeline and development structure.

To revert changes introduced in a specific commit B:

git revert B

Revert remote changes and modify history

You can undo remote changes and change history.

Even with an updated history, old commits can still be accessed by commit SHA. This is the case at least until all the automated cleanup of detached commits is performed, or a cleanup is run manually. Even the cleanup might not remove old commits if there are still refs pointing to them.

You should not change the history when you're working in a public branch or a branch that might be used by others.

NOTE: Never modify the commit history of your default branch or shared branch.

Modify history with `git rebase`

A branch of a merge request is a public branch and might be used by other developers. However, the project rules might require you to use git rebase to reduce the number of displayed commits on target branch after reviews are done.

You can modify history by using git rebase -i. Use this command to modify, squash, and delete commits.

#
# Commands:
# p, pick = use commit
# r, reword = use commit, but edit the commit message
# e, edit = use commit, but stop for amending
# s, squash = use commit, but meld into previous commit
# f, fixup = like "squash", but discard this commit's log message
# x, exec = run command (the rest of the line) using shell
# d, drop = remove commit
#
# These lines can be re-ordered; they are executed from top to bottom.
#
# If you remove a line THAT COMMIT WILL BE LOST.
#
# However, if you remove everything, the rebase will be aborted.
#
# Empty commits are commented out

NOTE: If you decide to stop a rebase, do not close your editor. Instead, remove all uncommented lines and save.

Use git rebase carefully on shared and remote branches. Experiment locally before you push to the remote repository.

# Modify history from commit-id to HEAD (current commit)
git rebase -i commit-id

Modify history with `git merge --squash`

When contributing to large open source repositories, consider squashing your commits into a single commit. This practice:

Helps maintain a clean and linear project history.
Simplifies the process of reverting changes, as all changes are condensed into one commit.

To squash commits on your branch to a single commit on a target branch at merge, use git merge --squash. For example:

Check out the base branch. In this example, the base branch is main:
```
git checkout main
```
Merge your target branch with --squash:
```
git merge --squash <target-branch>
```

Commit the changes:

git commit -m "Squash commit from feature-branch"

For information on how to squash commits from the GitLab UI, see Squash and merge.

Revert a merge commit to a different parent

When you revert a merge commit, the branch you merged to is always the first parent. For example, the default branch or main. To revert a merge commit to a different parent, you must revert the commit from the command line:

Identify the SHA of the parent commit you want to revert to.
Identify the parent number of the commit you want to revert to. (Defaults to 1, for the first parent.)
Run this command, replacing 2 with the parent number, and 7a39eb0 with the commit SHA:
```
git revert -m 2 7a39eb0
```

For information on reverting changes from the GitLab UI, see Revert changes.

Handle sensitive information

Sensitive information, such as passwords and API keys, can be accidentally committed to a Git repository. This section covers ways to handle this situation.

Redact information

Permanently delete sensitive or confidential information that was accidentally committed, and ensure it's no longer accessible in your repository's history. This process replaces a list of strings with ***REMOVED***.

Alternatively, to completely delete specific files from a repository, see Remove files.

To redact text from your repository, see Redact text from repository.

Remove information from commits

You can use Git to delete sensitive information from your past commits. However, history is modified in the process.

To rewrite history with certain filters, run git filter-branch.

To remove a file from the history altogether use:

git filter-branch --tree-filter 'rm filename' HEAD

The git filter-branch command might be slow on large repositories. Tools are available to execute Git commands more quickly. These tools are faster because they do not provide the same feature set as git filter-branch does, but focus on specific use cases.

For more information about purging files from the repository history and GitLab storage, see Reduce repository size.

Undo and remove commits

Undo your last commit and put everything back in the staging area:
```
git reset --soft HEAD^
```
Add files and change the commit message:
```
git commit --amend -m "New Message"
```
Undo the last change and remove all other changes, if you did not push yet:
```
git reset --hard HEAD^
```
Undo the last change and remove the last two commits, if you did not push yet:
```
git reset --hard HEAD^^
```

Example `git reset` workflow

The following is a common Git reset workflow:

Edit a file.
Check the status of the branch:
```
git status
```
Commit the changes to the branch with a wrong commit message:
```
git commit -am "kjkfjkg"
```
Check the Git log:
```
git log
```
Amend the commit with the correct commit message:
```
git commit --amend -m "New comment added"
```
Check the Git log again:
```
git log
```
Soft reset the branch:
```
git reset --soft HEAD^
```
Check the Git log again:
```
git log
```
Pull updates for the branch from the remote:
```
git pull origin <branch>
```
Push changes for the branch to the remote:
```
git push origin <branch>
```

Undo commits with a new commit

If a file was changed in a commit, and you want to change it back to how it was in the previous commit, but keep the commit history, you can use git revert. The command creates a new commit that reverses all actions taken in the original commit.

For example, to remove a file's changes in commit B, and restore its contents from commit A, run:

git revert <commit-sha>

Remove a file from a repository

To remove a file from disk and repository, use git rm. To remove a directory, use the -r flag:
```
git rm '*.txt'
git rm -r <dirname>
```
To keep a file on disk but remove it from the repository (such as a file you want to add to .gitignore), use the rm command with the --cache flag:
```
git rm <filename> --cache
```

These commands remove the file from current branches, but do not expunge it from your repository's history. To completely remove all traces of the file, past and present, from your repository, see Remove blobs.

Compare `git revert` and `git reset`

The git reset command removes the commit entirely.
The git revert command removes the changes, but leaves the commit intact. It's safer, because you can revert a revert.

# Changed file
git commit -am "bug introduced"
git revert HEAD
# New commit created reverting changes
# Now we want to re apply the reverted commit
git log # take hash from the revert commit
git revert <rev commit hash>
# reverted commit is back (new commit created again)