What Is a Terminal?

By the end of this lesson, you will understand what a terminal is, why it matters for working with AI tools, and you will have typed your very first commands into one. No prior experience needed — we start from zero.

🔍New to computers? What files and folders actually are

A file is a single piece of information stored on your computer — a document, a photo, a song, or a piece of code. Many files have extensions (like .txt for text, .html for a web page, .py for Python code), which often help software identify the file type — but not all files use extensions, especially on Linux and macOS.

A folder (also called a directory) is a container that holds files and other folders. Think of your computer like a filing cabinet: folders are the drawers and dividers, files are the individual papers inside.

When you use the terminal, you navigate this same filing cabinet — but by typing names instead of clicking icons. It’s the same files and folders you see in your regular file explorer, but a different interaction style — more precise, scriptable, and powerful once you learn the commands.

The two ways to talk to your computer

Right now, you’re using your computer through a graphical user interface (GUI). You click on icons, drag windows around, and use menus. It’s visual, intuitive, and how most people have always used computers.

But there’s a second way — one that’s been around even longer:

The terminal.

A terminal is a text-based interface where you type commands and your computer responds with text. No icons. No menus. Just you and your computer, having a conversation through typed messages.

The mental model: texting your computer

Here’s the simplest way to understand it:

Using a GUI is like talking to someone face-to-face — lots of gestures, pointing, visual cues.

Using a terminal is like texting them — you type exactly what you want, and they text back.

When you text a friend “send me that photo from last night,” they know exactly what to do. When you type ls in a terminal, your computer knows exactly what to do — it lists all the files in your current folder.

That’s it. That’s the whole concept. The terminal is a text conversation with your computer, and once you learn a handful of “phrases” (commands), you can ask it to do almost anything.

Why do you need this?

Every LLM CLI tool — Claude Code, Gemini CLI, Codex CLI, Copilot CLI — runs inside a terminal. That is not the only way to use AI building tools anymore — Claude Code now has a web version, and GitHub Codespaces gives you a terminal in your browser — but the terminal is still where these tools are most powerful and flexible. We cover those cloud sandbox options in Module 5, Lessons 4-5.

For now, learning the terminal gives you the most flexibility. To become an orchestrator, you need to be comfortable with two things:

Opening a terminal
Typing commands in it

You don’t need to become a command line wizard. You need maybe 10-15 commands, and we’ll teach you every single one.

💡It's less scary than it looks

The terminal feels intimidating because of how it looks in movies — green text on black screens, hackers typing furiously. In reality, it’s just a text box where you type simple English-ish commands. If you can text, you can use a terminal.

🧬In Your Field: Biotechclick to expand

If you’ve ever used R in the console, you’ve already used something very close to a terminal. The R console is a text interface where you type commands and get results back. The terminal has a similar interaction model (type a command, get output), but the shell controls your operating system and files, while the R console executes R code. AI CLI tools like Claude Code can help you write R scripts, manage data pipelines, and automate repetitive analysis tasks — all from the terminal.

📊In Your Field: MIS / Businessclick to expand

In the business world, you’ll often hear about “automation” and “scripting.” Those workflows live in the terminal. When an analyst says they automated a reporting pipeline, they likely wrote a series of terminal commands. AI CLI tools bring that same power to anyone willing to type a few commands — no programming degree needed.

🏛️In Your Field: Government / State Devclick to expand

Government IT environments often restrict what software you can install, but in many setups terminal access is available through approved tools (for example SSH gateways, bastion hosts, or managed cloud shells). SSH, remote servers, and secure cloud environments all use the terminal as their primary interface. Learning these basics will help you work within those constraints rather than around them.

What does it look like?

When you open a terminal, you’ll see something like this:

user@computer:~$

That’s called the prompt. It’s your computer saying “I’m ready — what do you want me to do?”

Your prompt may look different depending on your OS — for example, PS C:\Users\Name> in PowerShell on Windows, or name@MacBook ~ % on macOS. That’s normal. The core concept is the same: the prompt is waiting for your command.

Let’s break down each piece:

user — your username
computer — your computer’s name
~ — where you currently are (your home folder)
$ — the “I’m ready” symbol

You type a command after the $, press Enter, and the computer responds:

user@computer:~$ pwd
/home/user

pwd means “print working directory” — it tells you where you are in the filesystem. We’ll cover this in detail in Lesson 3.

Try it yourself

Here’s a practice terminal right in your browser. Type pwd and press Enter to see where you are, then try ls to see what files exist.

Claude Code — Practice Mode

Type a command and press Enter. Try: pwd, ls, cd projects, help

/home/user $

Don’t worry about breaking anything — this simulator is a safe sandbox. Type help to see all available commands.

Key vocabulary

Before we go further, here are five terms you’ll hear constantly:

Term	What it means	Analogy
Terminal	The application/window you type commands in	Your texting app
Shell	The program that interprets your commands	The “brain” that reads your texts
Command	An instruction you type	A text message
Directory	A folder	Same as a folder on your desktop
Path	The “address” of a file or folder	Like a street address

ℹTerminal vs Shell — what's the difference?

The terminal is the window. The Shell is the program running inside it. It’s like how Chrome (the window) runs a web engine (the program inside). Most of the time, you don’t need to think about this distinction — but if you see people mention " Bash " or “zsh,” those are shell names. For this course, we use bash, which is the most common shell on Linux and WSL (Windows Subsystem for Linux). If you’re on Windows without WSL, you may be in PowerShell, where command behavior can differ slightly. We’ll note alternatives when needed.

A worked example: your first “conversation”

Let’s walk through what an actual terminal session looks like, step by step. Think of it as reading a text conversation:

user@computer:~$ echo "Hello, terminal!"
Hello, terminal!

user@computer:~$ pwd
/home/user

user@computer:~$ ls
documents  projects  hello.txt

Here’s what happened:

You said: echo "Hello, terminal!" — The echo command repeats text back to you. It’s like asking the computer to say something out loud.
You asked: pwd — “Where am I right now?” The computer answered: /home/user (your home folder).
You asked: ls — “What’s in this folder?” The computer listed three items: two folders and a file.

That’s it — three commands, three answers. Every terminal session follows this same pattern: you ask, the computer answers.

What you’ll be able to do

By the end of this module (5 short lessons), you’ll be able to:

Open a terminal on any operating system
Navigate around your files and folders
Create, move, copy, and delete files
Connect to remote environments like servers and Codespaces
Feel confident when an AI tool says “run this command”

That’s the foundation. Once you have this, everything else — installing tools, running projects, deploying websites — becomes a matter of typing one or two commands.