FSlint is a utility to find and clean various forms of lint on a filesystem. I.E. unwanted or problematic cruft in your files or file names. For example, one form of lint it finds is duplicate files. It has both GUI and command line modes.

Dupemerge is described as 'Searches for identical files on a logical drive and creates hardlinks among those files, thus saving lots of hard disk space' and is an app in the os & utilities category. There are five alternatives to Dupemerge for Windows and Linux. The best Dupemerge alternative is FSlint, which is both free and Open Source. Other great apps like Dupemerge are FindDupe, Duplicate File Hard Linker, Duplicate Commander and FindLinks.
FSlint is a utility to find and clean various forms of lint on a filesystem. I.E. unwanted or problematic cruft in your files or file names. For example, one form of lint it finds is duplicate files. It has both GUI and command line modes.

Finddupe is a tool for quick detecting of duplicate files on a hard drive under Windows. Duplicate files can be detected, hardlinked, or deleted. Finddupe can also search for hardlinked files on your computer.

Small command line tool to reduce the size of duplicate files on one partition. Despite all other known tools the files in this implementation are not being listed, archived or removed but going to be hard linked using NTFS hard links. The tool runs in Windows NT 4.
Duplicate Commander is a free application designed to allow you to find and manage duplicate files on your computer. Duplicate Commander aims to be fast and easy to use. Version 3.0 sports a brand new interface, new search engine, and over 40 bug fixes.

FindLinks reports the file index and any hard links (alternate file paths on the same volume) that exist for the specified file. A file's data remains allocated so long as at it has at least one file name referencing it.