The Command Line — What It Is and How to Use It

Why This Guide Exists

Nearly every guide on this site — Docker, Git, Ollama, Pi-hole, self-hosting, Hermes Agent — asks you to type commands into a terminal at some point. If you've never used one before, those instructions can feel like being dropped into a foreign country without a phrasebook.

This guide is your phrasebook. Read it once, and every other guide on this site becomes easier. You'll learn what a terminal actually is, the handful of commands you'll use 90% of the time, and what to do on Windows vs Mac vs Linux.

Step 1. What Even Is a Terminal?

A terminal (also called a command line, shell, or console) is a text-based way to control your computer. Instead of clicking icons with a mouse, you type instructions and press Enter. The computer does what you asked and prints the result.

Think of it like texting your computer instead of using a remote control. It's faster for certain tasks — especially the kinds of things our guides cover: installing software, running servers, editing configuration files.

The terminal isn't a separate operating system. It's just a different way of talking to the same computer you already use. Everything you can do with a mouse, you can do in a terminal — and some things (like running Docker or starting a web server) are actually easier from the command line.

Step 2. Opening a Terminal on Your System

• •Windows — press the Windows key, type PowerShell or Command Prompt, and press Enter. Or, better yet, install WSL (covered in Step 3) to get a real Linux terminal on Windows.
• •Mac — open Spotlight (Cmd+Space), type Terminal, and press Enter. It's in Applications → Utilities if you prefer clicking.
• •Linux — look for "Terminal" in your applications menu, or press Ctrl+Alt+T on most distributions.

When you first open it, you'll see something like you@computer:~$ followed by a blinking cursor. That's called the prompt. It means the computer is waiting for you to type something.

Step 3. Windows Users: What is WSL and Do You Need It?

WSL stands for Windows Subsystem for Linux. It lets you run a real Linux terminal inside Windows — no virtual machine, no dual-boot, no separate computer.

Most of our self-hosting and developer guides assume a Linux-style terminal (bash). While PowerShell can do similar things, the commands are different. WSL gives you the same environment the guides expect, which means you can copy and paste commands without translation.

Installing WSL takes about 5 minutes:

Run that one command in PowerShell (as Administrator). Windows installs Ubuntu Linux automatically. After a reboot, you'll have an Ubuntu terminal available from your Start menu. That terminal uses bash — the same shell our Linux and Mac instructions assume.

Do you need WSL? If you're following our Docker, Git, Ollama, Pi-hole, or any self-hosting guide on Windows — yes, it'll make your life much easier. If you're just browsing guides without running commands, no.

Step 4. The 10 Commands You'll Actually Use

You don't need to memorise hundreds of commands. These ten cover the vast majority of what you'll encounter in our guides:

Step 5. What is Bash?

Bash (Bourne Again Shell) is the most common shell — the program that interprets what you type and runs the commands. It's the default on Linux and Mac, and what you get inside WSL on Windows.

When a guide says "run this in bash" or "open a bash terminal," it just means "use the normal terminal." Bash-specific features you might encounter:

• •Tab completion — start typing a filename and press Tab. Bash fills in the rest. Saves enormous time and prevents typos.
• •Up arrow — cycles through your previous commands. Don't retype something you ran two minutes ago.
• •Ctrl+C — stops whatever's currently running. If a command is taking too long or you ran the wrong thing, Ctrl+C kills it.
• •Ctrl+L — clears the screen (same as typing clear). Doesn't delete anything — just scrolls the terminal so you have a fresh view.

Step 6. Understanding Command Syntax

Commands in our guides follow a consistent pattern. Once you recognise it, you can read any command even if you've never seen it before:

• •command — the program you're running (docker, git, python, curl).
• •--flag — options that change behaviour. --help shows instructions, -y means "yes to all prompts," -d means "run in background." Single-letter flags use one dash (-d), full-word flags use two (--detach). They mean the same thing.
• •argument — the thing you're operating on: a filename, a URL, a folder path.

Real example from our Docker guide:

Broken down: docker (the program) run (what to do) -d (run in background) -p 8080:80 (map ports) --name webserver (give it a name) nginx (which image to use).