Fossil

** Undo the changes to the working checkout caused by the most recent
** of the following operations:
**
**    (1) fossil update             (5) fossil stash apply
**    (2) fossil merge              (6) fossil stash drop
**    (3) fossil revert             (7) fossil stash goto
**    (4) fossil stash pop
**
** The "fossil clean" operation can also be undone; however, this is
** currently limited to files that are less than 10MiB in size.
**
** If FILENAME is specified then restore the content of the named
** file(s) but otherwise leave the update or merge or revert in effect.
** The redo command undoes the effect of the most recent undo.
**
** If the -n|--dry-run option is present, no changes are made and instead
** the undo or redo command explains what actions the undo or redo would