I need an option that is the opposite of -bpa, that is, a listing of those addresses generated from a top-level address that have not yet been delivered.

Exim does not keep this information. It saves only the top-level addresses and the list of addresses that are finished with. At each delivery attempt, generated addresses are recomputed from scratch. This makes it possible to correct errors in redirection data that is causing delivery delays. However, there is an option you can set on a redirect router that changes things. It is called one_time, and if it is set, the list of generated addresses gets added to the top-level list at the first delivery attempt, and is never regenerated. Because top-level address lists must be real email addresses, this option cannot be used if any of the generated addresses are pipes, files, or autoreplies.

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