Thank you for creating and sharing this utility.
I ran it over my Postgres development directories that have almost identical files. It saved me about 1.7GB.
The project doesn't have any license associated with it. If you don't mind, can you please license this project with a license of your choice.
As a gesture of thanks, I have attempted to improve the installation step slightly and have created this pull request: https://github.com/ttkb-oss/dedup/pull/6