Undo commands, without a query or an error
See undo for an introduction to undoing commands.
The keyword command :ubt! is the same as :ubt, but
with a guarantee that it is ``error-free.'' More precisely, the value
returned by :ubt! will always be of the form (mv nil val state).
:Oops will undo the last :ubt!. See ubt, ubt?, ubu!, ubu, ubu?, and u.