Someone posted this on #siduction. Decent basic books
https://www.humblebundle.com/books/unix-book-bundle
I still have my Linux Pocket Guide (softcover) 2004 first edition.
They have epubs as well as pdf
The 10 Steps to Linux Survival is a very basic intro to some skills that are worth mastering.
peace out.
edited offer over.
Bundle is over right now >:(