Massively duplicated files are oftentimes a problem with music and movie collections. Because hunting for dupes by hand is definitely not the way to go, you may want to look to command-line tools like fdupes for help.
fdupes is available via apt-get in Ubuntu, so install it first:
sudo apt-get install fdupes
This is the basic syntax for looking up duplicated files:
fdupes -r [target-directory]
How to delete all duplicates and generate a report at the same time:
fdupes -rdN [target-directory] > textfile.txt
A quick overview of what the options mean:
- -r recursive, traverse subdirectories
- -d delete, delete duplicates
- -N keep the first file, remove other (duplicate) files
Needless to say: use this with caution! Files will be deleted forever.
Find more information on fdupes here (UbuntuGeek).