<a href="https://www.oreilly.com/library/view/linux-fundamentals-2nd/9780137929313/" rel="nofollow">https://www.oreilly.com/library/view/linux-fundamentals-2nd/...</a><p><a href="https://www.oreilly.com/library/view/fundamentals-of-linux/9781789530957/" rel="nofollow">https://www.oreilly.com/library/view/fundamentals-of-linux/9...</a><p><a href="https://training.linuxfoundation.org/oreilly/" rel="nofollow">https://training.linuxfoundation.org/oreilly/</a><p>Not sure about courses, but you can read their excellent books.