Table of Contents
Introduction
Command line skills turn Linux from a simple graphical desktop into a powerful, scriptable, and highly controllable environment. This part of the course focuses on interacting with Linux using text commands instead of only the graphical interface. You will learn how to open a terminal, run commands, read their output, and chain them together into repeatable workflows.
In this section you will not yet learn every possible command. Instead you will build a foundation that makes all later topics easier, including administration, scripting, and server work.
What You Will Learn in This Part
This part is organized into several chapters, each focusing on a different aspect of working at the command line. They are designed to build on each other and gradually expand what you can do.
You begin with the idea of a shell. The shell is the program that reads your commands, runs them, and shows the results. You will compare common shells such as Bash, Zsh, and Fish, understand the basic structure of a command, use environment variables, and access built in help. You also learn how to make the shell remember what you typed so you can repeat commands quickly with history and autocomplete.
After that, you move to files and directories. You will practice listing files, moving through directory trees, and creating, copying, renaming, and deleting files and folders. You will see how wildcards allow one short pattern to match many filenames and how to search the system for particular files or content inside files.
Once you can move comfortably around the filesystem, you will start viewing and editing text files. You will use simple viewing tools when you do not need to change anything, then edit files with beginner friendly editors in the terminal such as nano. You will also get a first look at the powerful editor vim. In this part you also learn how to redirect input and output so that commands can read from or write to files and other commands.
Because Linux is a multi user system, you need to understand how users, permissions, and ownership work. You will learn how the system decides who can read, write, or execute a file, how to change these permissions, when and how to change file ownership, and how to temporarily gain administrative powers with sudo.
With those basics, you are ready for package management from the command line. You will see how software repositories work and how to use different tools such as APT, DNF, and Pacman to install, remove, and update software. You will also look at universal packaging approaches like Snap, Flatpak, and AppImage, and how to keep a system up to date using these tools.
Next you will explore processes, which are running programs. You will learn what a process is, how to see which processes are active, and how to stop programs that misbehave. You will practice running jobs in the foreground or background, and get an initial understanding of long running system services and daemons.
Finally, you will create your first shell scripts. You will write simple scripts that combine commands into reusable tools, define and use variables, and control the flow of execution with conditionals and loops. You will also learn how to group commands into functions and make your scripts executable so that they can behave like normal commands.
Why the Command Line Matters
Graphical tools can be convenient for occasional use. However, the command line is more precise, more repeatable, and easier to automate. It also works the same way whether you sit at a physical machine, a virtual machine, or a remote server. Many advanced Linux tools are only available or are more powerful in the terminal.
In this part you will see how a short command can replace many clicks, how to repeat tasks exactly the same way every time, and how to save and share your work as simple text scripts.
Important: The command line is a core skill for any serious Linux user. Everything you learn here will be reused in later parts of the course, including system administration, security, DevOps, and cloud topics.
How to Practice This Part
To learn the command line, reading is not enough. You should have a Linux system ready to practice on, either installed directly, running in a virtual machine, or accessed through a remote server.
As you move through the chapters in this part, type every command yourself, observe what happens, then try small variations. You will make mistakes, but that is part of learning. The examples in later chapters will assume that you have practiced the basics from earlier ones, so it is worth taking the time to experiment now.
By the end of this part, you should feel comfortable opening a terminal, running and combining commands, browsing the filesystem, editing configuration files, managing software, and writing simple scripts that perform useful work. This confidence at the command line will support everything you do with Linux afterward.