If you would like to learn all about how linux works, and get a great head start on programming in 'c' for Linux then I highly recommend a book called 'The Linux Programming Interface' by Michael Kerrisk.
When I started searching for a guide on programming for Linux this was absolutely the best book that I bought. (It's available on Kindle too.)
As well as covering all the basics of Linux programming it gives incredibly useful details of how linux works, and the history of linux. I can't recommend it enough.