Ask HN: Where to find ressources to learn CLI magic?

Hi HN,

I stumbled upon this (https://news.ycombinator.com/item?id=8908462) amazing thread a while ago and would like to add up my bash / cli knowledge.

I've read a couple of Linux books and while some give an introduction into awk/sed/xargs i would love to learn more about them and other tools that i may not know about yet.

Does anyone know other good resources to learn about new commands / workflows?