This is why I like to always write any sort of user-script batch-job tools (backfills, purges, scrapers) with a "porcelain and plumbing" approach: The first step generates a fully declarative manifest of files/uris/commands (usually just json) and the second step actually executes them. I've used a --dry-run flag to just output the manifest, but I just read some folks use a --live-run flag to enable, with dry-run being the default, and I like that much better so I'll be using that going forward.

This pattern has the added benefit that it makes it really easy to write unit tests, which is something often sorely lacking in these sorts of batch scripts. It also makes full automation down the line a breeze, since you have nice shearing layers between your components.

http://www.laputan.org/mud/mud.html#ShearingLayers