I have a device running Ubuntu 18.04 that cannot be connected to the internet.
I would like to be able to update and install packages, but the standard
apt upgrade, and
apt install commands will not work.
What I believe I would need to do is run a command on the machine to collect what packages have been installed, take that information to another ubuntu machine to determine what packages are out of date and need to be updated, request the the packages to be updated or installed, and then take those packages back to the device and point apt at them.
I assume this need is not necessarily uncommon and there is a standard procedure for accomplishing it. How can I do this?