I think you want to have a save_environment("startup") operation
so that you can kill_to_saved_environment("startup"). Or some
other point.
I don't find this terribly important myself; I tend to write
a batch file and run it through. Then I diddle with the results
and then run it through again. That way I know that at the end
of the day I can reproduce the computation from a single file.
RJF