What are the differences between 'revert', 'amend,' 'rollback', and 'undo' a commit?

The terms revert and amend have a well defined meaning in Git. In contrast, rollback and undo do not have such a well defined meaning, and are open to interpretation.

Reverting a commit...

...means creating (on the current branch) a new commit that applies the inverse changes that another commit introduced. It's the preferred approach for correcting a problem in a repo that has already been shared with others, because it doesn't involve any destruction (i.e. rewriting history).

To revert a commit identified by <commit>, simply run

git revert <commit>

Amending a commit...

...means replacing the "current" commit by a new one that has the same parent(s); more details in How does git commit --amend work, exactly?

Be aware that

• amending a commit that you've already pushed to a shared remote is bad practice, because it's a form of history rewriting (it "deletes" the most recent commit, which your collaborators may have already based their work on);
• you can only amend the last commit on a given branch; to rewrite older commits, you need to bring out the big guns (e.g. interactive rebase).

To amend a commit, make all the required changes and stage them, then run

git commit --amend

No need to specify any commit, here, because the last commit on the current branch is the one that will be amended. Your editor will then pop up, giving you the opportunity to modify the commit message.

Rolling back...

...usually means discarding (or stashing) any local changes and resetting the branch to a commit (or simply checking out a commit, but that puts you in detached-HEAD state) prior to commit one where things started to get messed up. Use

git reset <commit-before-things-started-to-go-belly-up>

Undo a commit...

...can mean, depending on the context,

• revert a commit,
• amend a commit,
• remove a commit via an interactive rebase.

Undoing Changes: git checkout, git revert, git reset, git clean

• git revert: This command reverts the changes of a commit. it maintains track record in logs.

• git reset: This command reverts the changes of a commit. it does not maintain track record in logs i.e. reset to the reverted commit. Note: It an destructive function. have to be careful using this command.

• git reset --soft HEAD^ Undo last commit, put changes into staging

• git reset --hard HEAD^ Undo last commit and all changes

• git reset --hard HEAD^^ Undo last 2 commits and all changes

• git commit --amend where amend means add to the last commit. Sometimes we forgot to add files to commit. for example abc.txt file was forgot, we can add as follows: git add abc.txt and git commit --amend -m "New commit message"

Note: we don't have rollback and undo on this exact name either verbs or option.

git --amendYou should use the git --amend command only for commits which have not been pushed to a public branch of another Git repository. The git --amend command creates a new commit ID and people may have based their work already on the existing commit. In this case they would need to migrate their work based on the new commit

git revertYou can revert commits via the git revert command. This command reverts the changes of a commit.Such commits are useful to document that a change was withdrawn.

Here is a [enter link description here][1]

[1]: How do you roll back (reset) a Git repository to a particular commit? on rollback techniques