The first time you either see a . (dot) in a line of shell programming or someone tells you to source a file, you're first reaction is "huh?" I did it, and I even heard it in a colleague's voice on a phone call last week. My colleague was by no means a junior IT person, but I could still hear the confusion. I decided to try and clarify for some folks so they don't struggle as much as we did.
One of the most frustrating parts of learning to use Linux/Unix is when you mistype a command and then the error message pops up. None of us are perfect typists, and Linux/Unix commands can be long with multiple options. But there are ways to fix your mistakes without typing the whole command string again.
Keeping a computer logbook is not an option for most positions. If you’re working on your own, whether running your own site or just learning Linux/Unix, keeping records and notes are still important.
How often does the average computer professional have to create a brand new filesystem? Set up a new printer? Install security certificates? Patch the operating system? Unless you’re working in a large company, not that often.
From the very first day of training to be a Unix system administrator, I was warned about the dangers of working as root on a Unix system. There are some things that only root can do: change system configuration files, add users, update the system. But with great power, comes great responsibility. The responsibility to know when you are too tired, too angry, or too distracted to safely use that power.