Do you have lots of files? I do, particularly image files.
There are lots of duplicates and I want to extract a unique set from the larger set. That is what dupless does.
Written in Java, using sqlite, it is some simple code that solves the duplicate file problem.
All of the code is contained in the .jar file, both source and binary.
Currently it writes scripts for use on Linux or Windows.
See the Wiki or the README.txt in the .jar file for more information.