Like others here, I learned simply by doing and fumbling my way around until I was comfortable. That said, I think the most important thing for you to learn is

Like others here, I learned simply by doing and fumbling my way around until I was comfortable. That said, I think the most important thing for you to learn is how to get help. Learn how to find man(ual) pages, and how to interpret the very precise language and syntax that programmer-authors like to use. Then try reading the man pages of the systems that you want to learn - like 'man bash'. Also, some tools have nicer pages accessible via the 'info' command, so try 'info emacs'. That'll generally be the best way to learn how to use any tool. The only trick past that is to learn which tools exist, and google/stackoverflow will usually suggest appropriate tools when you tell it precisely which problem you want to solve.