New ask Hacker News story: Ask HN: How to learn about Linux system internals?

Ask HN: How to learn about Linux system internals?
2 by rory_isAdonk | 0 comments on Hacker News.
Coming from reading a SRE job posting at Google i saw: "Experience with algorithms and data structures and/or Unix/Linux systems internals (e.g., filesystems, system calls) and administration." I have a good grasp of algorithms, at least to the extent that I could further my knowledge in this domain alone. How would you suggest learning about Unix/Linux systems internals? I was thinking of setting up a linux server and managing it, any suggestions for good places to start in regards to practical things i could do with it which would expose me to the internals?