based sha1 expressions such as "<branchname>@\{yesterday}".
-f::
- Force the creation of a new branch even if it means deleting
- a branch that already exists with the same name.
+ Reset <branchname> to <startpoint> if <branchname> exists
+ already. Without `-f` 'git-branch' refuses to change an existing branch.
-m::
Move/rename a branch and the corresponding reflog.