Delete Random characters in filename?

the random characters are a machine-generated UUID, which (as you moticed) is always in the format 8-4-4-4-12: a total of 36 characters, plus the extension and punctuation for 41 characters. you can get rid of it with code like the following:

set txt to "some_file_name-xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx.mov"

set cleanTxt to text 1 thru -42 of txt

--> "some_file_name"

🙂

Just as an observation, I'm not sure why that UUID is getting added. The only time I ever see something like that is when the system needs to distinguish between otherwise duplicate files (e.g. if you put two copies of a file in the trash, or do some funky copying from the command line). My guess would be that you're having students upload files with the same name into a common folder. You'd do yourself a favor by stopping that practice. several ways to do it (I wrestled with this issue when I was teaching, so...):

• ask your students to append each file name with their student id. Easy to do, but big classes will only get you 80% compliance unless you threaten to dock points for it.
• create individual upload folders for each student. More maintenance involved in this, but it's more effective as well.
• set up a folder action that watches for new files and sorts/renames them based on file properties. this borders on power-scripting and is not for the feint-of-heart, but it removes the human element from the process as much as possible.

There are a couple of other tricks that might work, assuming that I have the right idea and depending on context. if you want to describe more of what you're doing we can see.

As a bash script:

#!/bin/bash

for f in ~/Desktop/*
do
    newname=$(echo "$f" | sed -E 's/[_-][A-Za-z0-9]{8}-[A-Za-z0-9]{4}-[A-Za-z0-9]{4}-[A-Za-z0-9]{4}-[A-Za-z0-9]{4}-[A-Za-z0-9]{8}//')
    if [ $f != $newname ]; then
        mv "$f" "$newname"
    fi
done

Searches for files in Desktop, edit to Folder as needed

Also, this will eliminate a dash or underscore before that string: [_-]

mght want to mention it to your professor. odds are s/he has the system misconfigured.