Linux Foundation Or edX Course
If you’d like to get a formal introduction to Linux, there’s no better way than to take part in the Introduction to Linux course presented by the Linux Foundation or the version provided via edX. In this course, you’ll learn all the basics you should know to become highly confident in your ability to use Linux.
The best part is that while you can pay a fee in order to formally complete the course, you’re also able to simply audit the course for free (via edX; a full free version of the intro course is coming soon via the Linux Foundation). This allows you to look at all the materials and partake in the lectures, but you won’t have any official certification that you’ve completed the course. If you’re just interested in taking the course for at-home Linux use, then there’s absolutely nothing wrong with going with the free, audit route.