find file duplicates on very large volume

[hart at nasw.org]

Another tack is to copy all the files and sort them into folders in the 
Finder using some scheme that makes sense, for example by year. Then 
buy DropStuff or StuffIt Deluxe and stuff the folders. You'd save 
enough space that you could ignore duplicates, or only toss ones that 
jump out at you when you're sorting. This is how I keep old work 
archives.

I tried Spring Cleaning and thought it was way too dangerous to fool 
with.

Stephen Hart
http://eugraph.com