Well, command line on your PC is likely going to take just as long because it

Aug 14, 2019
2:55:29pm

AggieWeekendCougar All-American

is searching over the network.

I haven't use a Seagate NAS before, but my Synology NAS lets me either
(1) open up a BASH shell when accessing it through the web interface
(2) enable SSH terminal login and then I can connect over SSH from my desktop

You can follow directions like

Unix & Linux Stack Exchange

Recursively delete all files with a given extension

I want to delete all *.o files in a directory and its sub-directories. However, I get an error:

https://unix.stackexchange.com/questions/116389/recursively-delete-all-files-with-a-given-extension

to learn how to use the 'find' command with wildcards and then pass the results to a command that will delete them. I highly, highly, HIGHLY recommend that if you do this, you first mess around with just the " find . -type f -name 'wildcard pattern' " portion first to make sure you have your wildcard right and it is only picking up the files you want it to.

Command line deletion in Linux is not an easily reversible process.