https://code.sololearn.com/W8iMGXTusS8V/?ref=app#html
So someone on sololearn made a nice html document that includes all these free pdf's in a number of computer programming languages
it's worth checking out and it certainly got its place in my bookmarks, along with the bellow links
https://github.com/PaulSec/awesome-sec-talks <- security / hacking talk videos
https://manual.cs50.net/seminars/ <- harvards cs50 free course!
http://www.allitebooks.com/ <- more free pdf's for everything Computers!
https://github.com/daryllxd/lifelong-learning/blob/master/the-first-20-hours.md <- a motivational and constructive paper to keep you learning at max capacity!
https://github.com/n1trux/awesome-sysadmin <- A curated list of amazingly awesome open source sysadmin resources.
And for the hardcore ones this course is old but gold!
http://www.cs.fsu.edu/~redwood/OffensiveComputerSecurity/lectures.html video course that takes you from C coding all down to exploit development reverse engineering and even physical security/social engineering!
Have a good one steemians!