starting download at byte x

Hello Forum,

I would like to start to download a file from a special position and not from byte 0. Do you know a way how I can make my user defined command to do that?

My motivation:
I have a usb memory stick with 256mb size. I want to download several 700mb files from two different locations (I call them L1 and L2). When at L1 I start to download maybe 200mb of the file. I want to take these 200mb with my memory stick with me to L2. There I start to resume the file and load another 100mb. Later when I am back at L1 I have not one byte of the file on my computer at L1. Now I want to start to download the file beginnnig at byte 300 million. From this position I download maybe another 200mb that I can take with my usb stick to L2 and append this fragment so I have a 500mb file that I can complete at L2.


My current user defined command