I'm using RMLINT as a substitute for DUPEGURU, which is CPU- and RAM-intensive. However, RMLINT doesn't give me the option of moving duplicate files to a new folder instead of deleting them -- a feature that DUPEGURU has and which I can't find on any command-line script.
This is important, especially when I'm new to RMLINT, to avoid accidental erasures by keeping duplicates for a while before deleting.

I see a feature request from 2017, though I don't know if it's been implemented.
It's hard to find a command-line script that does all I need, including
searching for duplicate files or folders
only matches with the same name
using a reference folder
selecting file types to delete by extension
dry runs
moving duplicate hierarchy to separate folder

Never used it (there are a plethora of CLI tools out there), but their own doco states:Most of the (useful) tools do likewise. It's just a script, hack it to your needs.

Edit: Missed the update as I was off looking for the doco. Get a tool that does most of what you want, and then manage it in the script. All the heavy lifting should be done for you.

That's a good idea. The rm command in the output file can be replaced with mv. But it helps to move the entire directory structure of duplicate files -- as dupeguru does. Dupeguru does everything I need, except it's so RAM/CPU-hungry that I can use it only on limited numbers of files.

I don't trust any script, app, or myself for that matter -- to handle this without error, which is why I insist on moving the files instead of deleting -- at least for a while.

I believe dupeguru does byte-for-byte comparison, which could account for its inefficiency. I can't find a switch to use only the hashing algorithm.

Thanks for your reply.