reflog

The reflog is a feature of the Git version control system that records changes to the tip of a reference, typically branches and tags, over time. When a commit is created, a branch is moved, or a reset or rebase changes the history, Git updates the reflog entry for the affected reference. Each entry records the commit’s hash, the action that caused the change, the time, and the author identity. This allows users to recover lost commits, identify where a branch moved from, or revert to a previous state even if that state is not reachable through the current branch history.

Reflog entries are stored in the .git/logs directory. For example, refs/heads/main has a logs/HEAD entry and a logs/refs/heads/main file that contain a sequence of entries. The HEAD reflog shows the movement of the current checked-out reference, while the branch reflogs keep a record of that branch’s updates. The history in reflogs can be inspected with git reflog, which prints entries in reverse chronological order, and filtered by branch name, using the format git reflog <ref>.

Git preserves reflog information for a configurable amount of time, defaulting to 90 days for HEAD and 30 days for other references. The reflog can be pruned with git reflog expire and git gc. Although reflogs can be a powerful recovery tool, they are not a substitute for proper backups or careful commit management. They also do not survive a repository push or clone unless the remote stores the reflog or the user exports it explicitly.