$40 seems kind of steep for a basic intro to commands like cp. I've managed to teach myself quite a bit from reading blogs and playing around with commands. The help and man documents help too. Are there any good resources (books or sites) for familiarizing myself more with the command line?
That is quite steep for a Linux tutorial. I personally learned and would recommend learning Linux by finding projects and doing the research to figure out how to do them. If you keep a mind for understanding you will find yourself learning how the commands work, along with a bunch of other valuable Linux information. And if you run into a dead end on research for a project, just ask about it here, or even on one of the multiple Linux IRC channels. One that I found decent help on was the Reddit Linux IRC channel "#r/linux". The Linux community has a few elitist annoyances, however in general I have found it to be a quite accepting community with many people who enjoy helping people understand Linux.
Whatever you end up doing, good luck, and have fun.
LOL just play around and learn. the tutorials are not worth it unless you going something advanced. there are plenty of tutorials here. A good linux distribution to get your feet wet is OpenSUSE 42.1 contrary to popular belief its actually easier to use than ubuntu.
If you want a good distribution to get good at the command line without it being too advanced you can be like me and start with Fedora
Its a common site to see people who started on a Red Hat based distribution to be far better linux unix and bsd users than people who started on ubuntu some of the easier debian derivatives because they basically got coddled and shielded away from the vast majority of big problems that can occur..
distro hopping is also a good thing if your new. after youve gotten comfortable. give manjaro and arch a try.. youll get fluent fast... linux is actually really easy
Decide on something you want to do, i.e. run a web server (LAMP), IRC or some game server. Throw in a firewall and learn about iptables or ufw (ubuntu's uncomplicated firewall). You'll find tutorials for all this and study the meaning of commands (not just copy/paste) that are listed there, what is piping |, what does &&, >, >> mean and so on.
There is also a lot to learn about the software you might use, how is running a database different on Linux than on Windows and so on.
edit: so no I wouldn't necessarily go for any paid tutorials unless this really matches your style of learning
Here's what I would suggest instead: Look up "Linux for beginners" on YT and check out a few videos, finding out what you like best and then moving forward from there. Surely there's a more thorough look at each command in the tutorial but that's what man pages are for. Otherwise there's stack overflow if you're having any issues.
You know what? In fact, if you're having any issues, I personally invite you to send me a DM and I'll help you myself.
I love Linux and what it stands for and that you can just learn by playing around with it.