undo the commands back up to (not including) a command descriptor
Major Section:  HISTORY

:ubu :x-3      ; undo the last three commands (same as :ubt :x-2)
:ubu (:x -3)   ; same as above
:ubu fn        ; undo back up to, but not including the introduction of fn
               ; (so fn will continue to be defined)
:ubu 5         ; undo back up to, but not including, the fifth command
               ; executed (leaving the first five commands in place)
See command-descriptor.

Ubu takes one argument, a command descriptor, and undoes the commands from :max (aka :x) up to, but not including, the indicated command. See command-descriptor.

Ubu can cause errors or queries. To avoid these, see ubu!.

Also see ubt, which is similar but also undoes the indicated command. As for :ubt, :oops will undo the undo (see oops) and ubu will not undo into ``prehistory''.

See u for how to undo just the latest command, and see ubt and see ubt! for how to undo back through (that is, including) the current command.