Automatic removal of files from network folders according to a given pattern?

Question

Computer networks

Due to the fact that nas, which is now responsible for storing files, does not support flexible restrictions on storing files with a certain extension, a utility is needed that will run through all folders and demolish everything that does not suit me (avi, mp3 ... well, etc.). Will there be ideas? Ideas for another storage implementation are not interesting. I know where and what .. but here what is with that and you have to work.
You also need to search for duplicate files using the same utility.
It is desirable to run all this from under the command line according to the schedule.

Answer 1

any script for deletion = critical in terms of consequences
look for duplicates = depending on what content

Answer 2

find / -name "*.mp3" -delete ? :-)
As for duplicates, you can't get by with a script, you need to make a database. In which to make a plate with the fields "file name" and "file hash". And then look for records where the "file name" is different, but the hashes are the same.