Fossil

** If the most recent command is not one of those listed as undoable,
** then the undo command might try to restore the state to be what it was
** prior to the last undoable command, or it might be a no-op.  If in
** doubt about what the undo command will do, first run it with the -n
** option.
**
** A single level of undo/redo is supported.  The undo/redo stack
** is cleared by the commit and checkout commands.  Other commands may
** is cleared by the commit and check-out commands.  Other commands may
** or may not clear the undo stack.
**
** Future versions of Fossil might add new commands to the set of commands
** that are undoable.
**
** Options:
**   -n|--dry-run   Do not make changes but show what would be done