@wt_101 If I can suggest you look at this post: https://forums.fogproject.org/topic/11126/using-fog-postinstall-scripts-for-windows-driver-injection-2017-ed
it gives you an idea how to do this with windows. You can use the same concept, except for maybe look for the partition that has an /etc directory.
Here is a bit older script that shows a few different techniques. https://forums.fogproject.org/topic/7740/the-magical-mystical-fog-post-download-script