[ Lots of tutorials on sysadmin and other backend technology ]
https://www.digitalocean.com/community

[ What should a self-taught programmer study? ]
https://news.ycombinator.com/item?id=7612783

[ Various ressources for further reading ]
http://maxehmookau.github.io/blog/2014/04/28/the-graduate-software-developers-reading-lis/