The terminal (also called command line, shell, or console) is a text-based way to control your computer. Instead of clicking buttons and icons, you type commands.

It looks intimidating at first. But once you learn 10-15 commands, you’ll wonder how you ever lived without it.

Why developers use the terminal

• It’s faster. Renaming 500 files takes one command, not 500 clicks.
• It’s more powerful. Many developer tools only work from the terminal (Git, npm, Docker).
• It’s scriptable. You can save commands in a file and run them automatically.
• Servers don’t have GUIs. When you manage a server, the terminal is all you have.

Opening the terminal

• macOS: Cmd+Space → type “Terminal” → Enter (or use iTerm2)
• Windows: Search “PowerShell” or install Windows Terminal
• Linux: Ctrl+Alt+T (or search “Terminal”)

Essential commands

Moving around

pwd                    # Where am I? (Print Working Directory)
ls                     # List files in current directory
ls -la                 # List ALL files with details (including hidden)
cd Documents           # Go into the Documents folder
cd ..                  # Go up one level
cd ~                   # Go to home directory
cd /                   # Go to root directory

Files and folders

mkdir my-project       # Create a folder
touch index.html       # Create an empty file
cp file.txt backup.txt # Copy a file
mv old.txt new.txt     # Rename (or move) a file
rm file.txt            # Delete a file (no trash — it's gone!)
rm -r folder/          # Delete a folder and everything in it

Reading files

cat file.txt           # Print entire file
head file.txt          # First 10 lines
tail file.txt          # Last 10 lines
tail -f log.txt        # Follow a file (see new lines as they're added)
less file.txt          # Scroll through a file (press q to quit)

Searching

grep "error" log.txt           # Find lines containing "error"
grep -r "TODO" src/            # Search recursively in a directory
find . -name "*.js"            # Find files by name
find . -name "*.log" -delete   # Find and delete

System info

whoami                 # Current user
hostname               # Computer name
df -h                  # Disk space
free -h                # Memory usage (Linux)
top                    # Running processes (Ctrl+C to exit)

Keyboard shortcuts

These work in most terminals and will save you a lot of time:

Shortcut	What it does
Tab	Autocomplete file/folder names
↑ / ↓	Previous / next command from history
Ctrl+C	Cancel current command
Ctrl+L	Clear the screen
Ctrl+A	Jump to beginning of line
Ctrl+E	Jump to end of line
Ctrl+R	Search command history

Tab completion is the most important one. Start typing a filename and press Tab — the terminal fills in the rest.

Pipes and redirection

This is where the terminal gets powerful — combining commands:

# Pipe: send output of one command to another
ls | grep ".js"                    # List only .js files
cat log.txt | grep "error" | wc -l  # Count error lines

# Redirect output to a file
echo "hello" > file.txt            # Write (overwrites)
echo "world" >> file.txt           # Append

# Redirect errors
command 2> errors.txt              # Save errors to file
command > output.txt 2>&1          # Save everything to file

Installing things

# macOS (Homebrew)
brew install node
brew install git

# Ubuntu/Debian
sudo apt update
sudo apt install nodejs

# Any OS (Node.js packages)
npm install -g typescript

See: Homebrew cheat sheet for macOS package management.

Next steps

1. Open your terminal right now
2. Type pwd to see where you are
3. Type ls to see what’s there
4. Navigate to a project folder with cd
5. Check out the Linux Terminal cheat sheet and Bash cheat sheet for more commands