How to merge folders and subfolders?

Solution 1:

Try:

rsync -aP /ORIGINAL_A/* /DESTINATION_C/

This is like a copy of the folder A

rsync -aP /ORIGINAL_B/* /DESTINATION_C/

That should sync the folders A an B to another the new folder C.

You could sync the file from A to B directly but you don't will have data loss this way.