Environment Basics

No programming experience required. Here’s a collection of basic knowledge for understanding your development environment.

Terminal Basics

What is a Terminal?

A screen for giving text commands to your computer. It’s also built into VS Code.

How to open Terminal in VS Code:

• Menu: “Terminal” → “New Terminal”
• Shortcut: Ctrl + `` (backtick)

Stop with Ctrl+C

One of the most important operations.

When you want to stop a server or running program:

Ctrl + C

(Use Ctrl even on Mac, not Cmd)

When to use:

• Stopping a development server
• When stuck in an infinite loop
• When thinking “This command is taking forever…”

How to Read Commands

npm run dev

Meaning: “Use npm to execute the script named dev”

Common Commands

How to Read Error Messages

Don’t panic when you see red text.

Points to look at:

1. Lines near the end - The cause is written there
2. Filename and line number - Where the problem occurred
3. Error type - Text after Error:

Error: Cannot find module 'express'
    at Function.Module._resolveFilename (node:internal/modules/cjs/loader:933:15)
    at /Users/you/project/app.js:1:15

→ Can’t find module “express”, at app.js line 1, character 15

Solution: Just show the error message to Claude.

Files and Folders

Project = Folder

Think of it as: 1 app/tool = 1 folder.

my-first-app/          ← This is the "project"
├── index.html
├── style.css
└── script.js

“Opening a folder” in VS Code = working on that project.

File Extensions

The part after . in the filename tells you the file type.

Hidden Files

Files and folders starting with . are “hidden files”.

.env           ← Environment variables (secrets)
.gitignore     ← List of files Git should ignore
.vscode/       ← VS Code settings

Normally invisible, but these are important project files.

They’re visible in VS Code, so keep them in mind.

How to Read Paths

A string representing a file’s location is called a “path”.

If confused, just ask Claude.

Git Basics

What is Git?

A tool for managing file change history.

Capabilities:

• Record when, who, and what changed
• Revert to previous versions
• Multiple people editing the same project

Basic Terms

GitHub

A service for managing and sharing Git repositories online.

Uses:

• Code backup
• Team collaboration
• Publishing and sharing

Install Commands

npm install

Installs required packages for Node.js/JavaScript projects.

# Install all packages listed in package.json
npm install
 
# Install specific package
npm install package-name

Creates node_modules/ folder where packages are stored.

pip install

Installs required packages for Python.

# Install specific package
pip install package-name
 
# Install all packages listed in requirements.txt
pip install -r requirements.txt

Common Situations and Solutions

”npm: command not found”

Node.js is not installed.

→ Ask Claude “How do I install Node.js?"

"permission denied”

No permission.

→ Consult Claude. Avoid using sudo carelessly.

”module not found”

Required package is not installed.

→ Run npm install or pip install package-name.

Terminal Became Unresponsive

If it stops accepting input:

1. Press Ctrl + C several times
2. If that doesn’t work, open a new terminal (“Terminal” → “New Terminal”)

Working with Claude

Even without this basic knowledge, you can ask Claude to explain.

"What's a terminal?"
"I got an error with npm install. Look at this"
"What does this terminal output mean?"

Don’t hesitate to ask Claude about anything you don’t understand. Showing error messages or screenshots gets you more accurate answers.

Next Steps

Now that you have the environment basics, check out Development Fundamentals next.