[Lilux-help] Duplicate files

[Patrick Useldinger]

Does anybody know of a tools that *reliably* finds duplicate files?

I am using rsync to backup my machines on a single spare disk. As this 
disk will mirror all files I consider backupworthy, the tool should find 
them in this central place. I then want to delete the dups except one on 
the source machine, and rsync again.

I do not want to replace dups by hard links, as I suppose that that 
would mess up the followingr sync.

Any ideas?