Backtracking #

We already saw how a file can be unstaged (with git reset) before it is committed.

If the file was committed by mistake, then there are at least three scenarios.

Reset #

If the commits that contain the file have not been shared yet with a remote, then these commits can be cancelled locally. The command

git reset <ID>

moves the pointer for the current branch “back in time” to the commit <ID>. This has the effect of deleting all posterior commits.

Revert #

If the commits that contain the file have been shared with a remote, then git revert is often recommended by default.

This command does not affect the history of a branch (as opposed to git reset). Instead, if adds a commit to the history that reverts the k last commits on the current branch.

For instance

git revert HEAD

adds a commit that reverts the latest one.

And

git revert HEAD~3..

adds a commit that reverts the 3 latest ones.

Rewriting history #

In some (rare) scenarios, one may need to rewrite the history of a branch that has already been shared.

For instance, sensitive information (passwords, etc.) or a large dataset may have been committed by mistake.

Dedicated tools may be used in such scenarios.