There is so much to learn about programming and computer science. It is impossible to remember it all.
My advice for all beginners is to start a learning log. The goal is to have an indexed library (or second brain) which you can quickly retrieve information from. My only recommendation is that you use a note-taking app. I love paper, but it's hard to flip through hundreds of bash commands quickly.
Whenever you learn something interesting, cool, or important, write it down. Throughout the working day, if I find something cool, I write it on a post-it note. When I have some downtime, I add this information to my library.
At work, you might find special processes to follow, new architecture, or custom modifications. I write these down too, so I don't have to ask twice.
My colleagues think I have a great memory, but it's only a great filing system and a little bit of effort each day. Shh... don't tell anyone!