Finding / Listing only hard linked duplicates

What jdupes version are you using?

jdupes 1.20.2 (2021-11-02) 64-bit

Where did you get your copy of the jdupes binary?

[ ] Official binary from jdupes releases [x] OS distribution repository (Linux, Homebrew, etc. - put distro's name/version in text block below) [ ] I personally compiled it from source code (paste your build commands in the text block below) [ ] Other (please explain below)

Debian bookworm / sid

Have you searched in Issues?

[x] I have searched for my problem in Issues and I am confident that this is not a duplicate of a previous reported issue or feature request.

I have done my due diligence

[x] I am not suggesting changing the hash algorithm, storing files in a database, comparing file data blocks differently, suggesting that file sizes should be used before comparison, or other common suggestions that indicate I haven't read the documentation, code, or examined the issue tracker entries to discover that all of these things have already been implemented or won't make a difference if they were implemented. I have done my due diligence before asking for help or making a suggestion.

Issue or feature request details

I would like to have a feature similar to --hard-links, however limited to finding already hard linked files. I tried searching other for tools which might already implement this, however I did not found any which can do that and output the results similar to jdupes (grouped).

I request this feature because it should be complementary to what jdupes already can do. I would like to have this feature to see which files were hardlinked after I ran jdupes --recursive --link-hard on a given directory to e.g. know, if I need to be cautious about modifying files from my archives because I might also "change other files" (the content in other paths) I still want to keep as they are now. Also I could use this to e.g. see where directory trees might be similar (nearly all files except a few are equal) to one another.

This is a good idea and is actually something I'm planning to implement.

I was also looking for this same functionality. When I realized such functionality was not already implemented, I looked through the existing feature requests and found that someone had already suggested it. I suspect this feature will be a valuable addition to many. Thanks for all your hard work @jbruchon!