Outside contractor says they need read/write/execute permissions on part of the filesystem so they can run a script.

I'm ok with that, but I want to know what they're running, in case it turns out there is some nefarious code. I assume they are going to upload the file, run it, and then delete it to prevent me from finding out what they've done.

How can I find out exactly what they've done? My question specifically asks for a way of automatically copying the file, which would be one way. But if you have another solution, that's fine.

For example, if the file could be automatically copied to /home/root/uploaded_files/ that would be awesome.