FDUPES
FDUPES is a program for identifying or deleting duplicate files
...Once duplicates are identified, the tool offers interactive deletion options where users can choose which copy to keep and which to remove, or apply flags to automate deletion while preserving a single instance. Because it operates directly on file content rather than just filenames, fdupes can accurately detect true copies and guide cleaning operations in data cleanup or migration tasks. It’s a simple, efficient, and widely used utility on Unix-like systems, appreciated by administrators, developers, and power users.