git-reflog - Manage reflog information
git reflog <subcommand> <options>
The command takes various subcommands, and different options depending on the subcommand:
git reflog [show] [log-options]
Reflog is a mechanism to record when the tip of branches are updated. This command is to manage the information recorded in it.
The subcommand "expire" is used to prune older reflog entries. Entries older than expire time, or entries older than expire-unreachable time and are not reachable from the current tip, are removed from the reflog. This is typically not used directly by the end users — instead, see gitlink:git-gc.
The subcommand "show" (which is also the default, in the absence of any subcommands) will take all the normal log options, and show the log of HEAD, which will cover all recent actions, including branch switches. It is basically an alias for git log -g --abbrev-commit --pretty=oneline, see gitlink:git-log.
This revamps the logic — the definition of "broken commit" becomes: a commit that is not reachable from any of the refs and there is a missing object among the commit, tree, or blob objects reachable from it that is not reachable from any of the refs.
This computation involves traversing all the reachable objects, i.e. it has the same cost as git prune. Fortunately, once this is run, we should not have to ever worry about missing objects, because the current prune and pack-objects know about reflogs and protect objects referred by them.
Entries older than this time are pruned. Without the option it is taken from configuration gc.reflogExpire, which in turn defaults to 90 days.
Entries older than this time and are not reachable from the current tip of the branch are pruned. Without the option it is taken from configuration gc.reflogExpireUnreachable, which in turn defaults to 30 days.
Instead of listing <refs> explicitly, prune all refs.
Written by Junio C Hamano <email@example.com>
Documentation by Junio C Hamano and the git-list <firstname.lastname@example.org>.
Part of the gitlink:git suite