"1 Preliminary Note
I will show how to do this on the desktop (with Synaptic) and on
the command line. I'm using a USB stick to store the text file;
that way I can simply plug in the USB stick with the text file into
the other computer and start the package installation there.
"If you try this, please make sure the the file
/etc/apt/sources.list is identical on both systems (if you like,
you can also copy that file to the USB stick so that it can be used
on the other computer)."