That tool looks fairly old considering it’s talking about sorting inodes and benchmarking on spinning disk. Is there any tool that replaces with a COW copy instead of creating a hard link? COW is strictly a safer way to do this compression and honestly it seems like something filesystems should do automatically, perhaps with FastCDC deduplication.

Yes, that would be safer when available (although generally files within library dependencies are not modified I think?). It looks like fclones implements this, is faster and is written in Rust https://github.com/pkolaczk/fclones (the last is the most important point of course /s).

Fantastic. Now that’s a tool I’d run as it seems actually safe.

rdfind doesn’t limit itself to library dependencies so I’d be worried about it fucking up on files I’d rather not have be hardlinked just because a copy exists (eg 2 checked out git clones where modifying the code in one suddenly starts modifying files in the other)