Content Based Query Install

Throwing documents into my document archive, I realize one of the forms of semantic exposure of deduplication that I want:

When I say "put(file)", if file is already in the archivem I want to get told "Hey, you, the file is already in the archive!!!

Perhaps not under the name I want to put it in.

put(Archive,nameInArchive,file) => warn if already there

put(Archive,nameInArchive,file,force=1) => force install, even if already there


Interactively, I want the default o be "don't install if already there".