Not a particulary clever program.
But one of my other "Forth" programs is able to scan files in a directory structure and build a database of file information. This includes file size, last modified date,…
I use it to identify whether multiple copies of a file exist. How? By including a SHA1 hash value in the database.
This "hash file" program uses the same hash routines.
The executable is available via the following link: PlodWare Hash File