`(require 'find-dupes-dired)` and Run `find-dupes-dired`.

It needs "fdupes" in gnu/linux or "jdupes" in Windows, or others by setting
`find-dupes-dired-program` and `find-dupes-dired-ls-option`.

Thanks [fd-dired](https://github.com/yqrashawn/fd-dired/blob/master/fd-dired.el)
and [rg](https://github.com/dajva/rg.el). I got some references from them.