Find books in one library not in another?
I have 2 libraries for Calibre. My current one and a very old one.
I know in the old one there are several books in the old one not in the current one.
Is there a way to compare the 2 libraries and mark the books in the old library that aren't present in the current one so that I can import them into the current one and delete the old one?
I suspect this may be plug-in territory but I haven't found one that does this.
Any hints / suggestions most welcome.