Rebase

Rebase is an operation in version control systems that moves or reorganizes a sequence of commits to a new base commit. In Git, rebase works by reapplying the commits of one branch on top of another branch, producing new commits with different identifiers. The effect is a linear history where the feature branch appears to have been created from the tip of the base branch.

If you want to move a branch to start from another base, you run git rebase <upstream> while on the branch to be rewritten. Git determines the common ancestor, resets the branch to the target base, and replays each commit from the original branch. The result is a linear sequence of commits; you can adjust behavior with options such as --onto and related forms.

Interactive rebasing, invoked as git rebase -i, offers editing, reordering, squashing, rewording, or removing commits. It is commonly used to tidy a set of commits before sharing or merging, for example by combining small fixes into a single commit or improving commit messages.

Rebase vs merge: Rebase rewrites history and avoids creating merge commits, while merge preserves the exact history and creates a merge commit. Rewriting public history can disrupt collaborators and may require force pushes to update remote branches.

Best practices: use rebase on private or feature branches, keep main branches intact, and coordinate with teammates before rebasing shared history. If a branch has already been published, consider merging instead, or obtain consensus to rebase and use git push --force-with-lease to update the remote branch safely.