find dupes recursively starting at foldername:
fdupes -r foldername
Use the following to get prompted to delete duplicates:
fdupes -r -d foldername
There is also a package called FSlint which has a GUI too.

Technical notes, and other ideas.
find dupes recursively starting at foldername:
fdupes -r foldername
Use the following to get prompted to delete duplicates:
fdupes -r -d foldername
There is also a package called FSlint which has a GUI too.