merging files (Kubuntu)

[accessys at smart.net]

when I merge directories that have a lot of identical files in them it 
seems to only allow a complete replacement of all files, or having to 
manually skip each duplicate file...  prefer doing this in "X" rather than 
in terminal.  would much like to merge the directories getting only the 
non duplicate files and directories added to the existing directory and 
files.

Bob