Ok so a little clarification.
The specific idea I have in mind is to have my Raspberry Pi monitor my network for a successful ping to my phone's IP address. If it reads that address on the network, I need it to empty a particular folder on my phone that I use to store pics. If the pi sees anything at all, it's to assume that it needs to relocate everything in that folder to my NAS. Maybe I took pics a given day, maybe I didn't. I've got the network monitor code built and tested, I've got the NAS transfer figured, just need to know how to get the pi to query my phone.
More generally, I have a lot of other ideas for the script once I've got a lot more experience. One idea I think would be really cool is having one Pi able to query another Pi's network interfaces file after a fresh OS install and automatically write custom IP settings to the file.
Kinda the general idea: one machine on the LAN queries a directory on another device, then does something based on the true/false return.