Command Line Basics

What is the Command Line?

The command line (also called the terminal, shell, or console) is a text-based interface for interacting with your computer. Instead of clicking icons, you type commands. It's faster, more powerful, and essential for development workflows.

Windows (PowerShell / Command Prompt) vs Unix (Terminal)

Most development tools and tutorials assume a Unix-like environment (Linux/macOS Terminal). On Windows, you can use PowerShell, WSL (Windows Subsystem for Linux), or Git Bash.

Essential Navigation Commands

# Print current directory
pwd

# List files in current directory
ls          # Unix/macOS
dir         # Windows

# List files with details
ls -la      # Hidden files too

# Change directory
cd foldername     # Go into folder
cd ..             # Go up one level
cd ~              # Go to home directory

# Create a directory
mkdir new-folder

# Remove a file
rm filename.txt

# Remove a directory (be careful!)
rm -rf folder-name

# Copy a file
cp source.txt destination.txt

# Move / Rename a file
mv oldname.txt newname.txt

File Reading Commands

# Print file contents
cat filename.txt

# View file one page at a time
less filename.txt

# Show first 10 lines
head filename.txt

# Show last 10 lines
tail filename.txt

Useful Tips

• Tab completion — Press Tab to auto-complete file/folder names.
• Up/Down arrows — Navigate through previous commands.
• Ctrl + C — Cancel a running command.
• Ctrl + L — Clear the terminal screen.
• Pipe (|) — Send output of one command to another: ls | grep ".js"
• Redirect (>) — Save command output to a file: ls > files.txt

Running Programs

# Run a Node.js script
node app.js

# Install npm packages
npm install

# Start a development server
npm run dev

# Run Python script
python script.py

What's Next?

Use these commands with Git & GitHub, or explore Cheat Sheets for quick command references.