In my experience learning something comes from playing with it. So allow me shameless plug: https://archive.is/xDb8o This is a Linux tutorial I wrote quite some time ago but it's still relevant, it tries to give you some hands-on overview of Linux system by having you to execute commands and understand the output.
It goal is to just go through it to familiarize yourself with different parts of the systems. There is verbose table of contents on the first page if you scroll down.
It goal is to just go through it to familiarize yourself with different parts of the systems. There is verbose table of contents on the first page if you scroll down.