CompTIA A+ Core 2 (220-1202), Domain 1, Objective 1.9 focuses on working with Linux from the command line, including its common text editors and the core operating-system components that make a Linux system run. Even in a predominantly Windows shop, technicians routinely touch Linux on servers, appliances, network gear, and cloud instances, where editing a configuration file and restarting a service are everyday tasks performed entirely at a terminal.
In this article you'll learn basic editing, saving, and quitting in the nano and vi/vim text editors, and how the key Linux OS components fit together: systemd as the init system and service manager (via systemctl), the kernel and how to query it with uname, and the GRUB bootloader that starts it all.