Humble Ebook Bundle for O'Reilly UNIX books.
Dec 1, 2016 by Nicholas P Cochrane
For anyone interested in learning UNIX, Linux, Bash, Emac, Vim, etc. Humble Bundle has a collection of DRM free O'Reilly of books for 1 dollar for the basics to 15 dollars for 16. If you don't want to buy them, there is also a small bash introduction book that you can get for free.
Edit: The embedded link wasn't showing up so here is the URL