Updating recordings

undo recording-update loads an Undo recording and saves it, or a selected portion of its execution history, as a new recording.

This may be useful in the following circumstances:

  • You have a recording created by an old version of the Undo Engine. By converting it to the latest recording format, you can take advantage of improvements in more recent versions of Undo, such as smaller recording sizes, and faster loading times.

  • You have a very large recording, but only a small range of the execution history is relevant to the bug you are investigating. By updating the recording to contain just the range of interest, you can reduce the recording size and loading time.


    The Time limits feature should normally be used instead to prevent execution from going outside a range of bbcounts in execution history. Time limits are quicker and more flexible than updating the whole recording. However, updating may be useful if you need to copy the recording to multiple machines, or expect to have to load it many times in the course of investigating a bug.

Usage synopsis



--begin TIME, -b TIME

Beginning of the part of execution history to keep.

--end TIME, -e TIME

End of the part of execution history to keep.

--help, -h

Display help message and exit.

--version, -v

Print version information and exit.

In the --begin and --end options, the argument TIME must be one of the following, where N is a number:


Absolute bbcount.


Number of bbcounts after the beginning of execution history.


Number of bbcounts before the end of execution history.


Percentage through execution history.