🚀 go-pugleaf

I want to filter out all of the duplicate messages from my mailbox.  That is,
if two or more messages have the same Message-Id, I want to delete all but
one of them.  How can I do this?

One approach might be to use the pipe command to send all of the mail text
to a unix script that searches for duplicates.  Is there a way for this script
to communicate the list of duplicates back to a mush pipeline?  E.g.,
something like this:

    pick * | pipe myfilter | delete

I couldn't find anything in the man pages about getting a message list
*out* of the pipe command.

Thanks.

-Joe