Terminal Commands Every AI Developer Must Know

Navigation — Where Are You?

pwd              # Print working directory — shows your current location
ls               # List files in current directory
ls -la           # List all files including hidden (.dotfiles) with details
cd myproject     # Change into the 'myproject' directory
cd ..            # Go up one directory level
cd ~             # Go to your home directory
cd -             # Go back to the previous directory

The most important habit: always know where you are before running commands. pwd tells you. Running npm install in the wrong directory is a common source of confusion.

Files and Directories

mkdir my-project         # Create a directory
mkdir -p a/b/c           # Create nested directories (no error if exists)
touch filename.txt       # Create an empty file
cp source.txt dest.txt   # Copy a file
cp -r source/ dest/      # Copy a directory and all its contents
mv old.txt new.txt       # Move or rename a file
rm filename.txt          # Delete a file (no trash — gone immediately)
rm -rf directory/        # Delete a directory and all contents (CAREFUL)
cat file.txt             # Print file contents to terminal
head -20 file.txt        # Show first 20 lines of a file
tail -f app.log          # Stream a log file in real time (follow)
grep "error" app.log     # Search for "error" in a file

npm and Package Management

npm install                     # Install all dependencies from package.json
npm install express             # Install a package and add to dependencies
npm install --save-dev eslint   # Install as dev dependency
npm install -g nodemon          # Install globally (available system-wide)
npm uninstall express           # Remove a package
npm run dev                     # Run the 'dev' script from package.json
npm run build                   # Run the 'build' script
npm run lint                    # Run the 'lint' script
npm list                        # List installed packages
npm outdated                    # Show packages with newer versions available
npm update                      # Update all packages to latest minor versions
npx create-next-app my-app      # Run a package without installing globally

npx is particularly important — it runs a package directly from the npm registry without a global install. AI tools use npx for one-time setup commands like npx prisma migrate dev or npx eslint --init.

Process Control

Ctrl+C                  # Stop the currently running process (dev server, etc.)
Ctrl+Z                  # Suspend a process (send to background)
Ctrl+D                  # Exit the current shell session

ps aux                  # List all running processes
ps aux | grep node      # Filter processes containing "node"
kill 12345              # Kill process with ID 12345 (graceful)
kill -9 12345           # Force kill a process (immediate, no cleanup)
lsof -i :3000           # Show what is using port 3000
lsof -ti :3000 | xargs kill -9  # Kill whatever is running on port 3000

The lsof -ti :3000 | xargs kill -9 command is invaluable when your dev server crashes and leaves the port occupied. "Address already in use" errors are solved with this pattern.

Environment and Variables

echo $HOME              # Print an environment variable value
echo $NODE_ENV          # Check the current environment
export PORT=4000        # Set an environment variable for this session
env                     # List all current environment variables
env | grep PORT         # Find specific environment variables

# Running with environment variables inline
NODE_ENV=production node server.js
DATABASE_URL=postgres://... npm run migrate

Git Quick Reference

git status              # See changed files
git add .               # Stage all changes
git commit -m "message" # Commit staged changes
git push                # Push to remote
git pull                # Pull latest changes
git log --oneline       # Compact commit history
git diff                # See unstaged changes
git stash               # Temporarily save uncommitted changes
git stash pop           # Restore stashed changes
git checkout -b feature # Create and switch to a new branch

Searching

# Find files by name
find . -name "*.json" -not -path "*/node_modules/*"

# Search inside files
grep -rn "TODO" --include="*.ts" .
grep -rn "dangerouslySetInnerHTML" --include="*.tsx" .

# Search with context lines
grep -rn -A 2 -B 2 "api_key" .  # Show 2 lines before/after each match

The grep search pattern is critical for security audits — search for dangerouslySetInnerHTML, eval(, or innerHTML = to find potential XSS vulnerabilities in AI-generated code.

Reading Output and Pipes

# | (pipe) sends output of one command to another
ls -la | grep ".json"       # Filter ls output to .json files
cat package.json | grep name # Find name in package.json

# > redirects output to a file
npm run build > build.log 2>&1  # Save build output to file (including errors)

# && runs second command only if first succeeds
npm install && npm run build

# || runs second command only if first fails
npm test || echo "Tests failed"

Terminal Shortcuts

• Tab — Autocomplete file names and commands
• ↑ / ↓ — Navigate command history
• Ctrl+R — Search command history
• Ctrl+L — Clear the terminal screen (keeps history)
• Ctrl+A — Jump to beginning of line
• Ctrl+E — Jump to end of line
• Ctrl+W — Delete the word before cursor

What to Learn Next

• What Is Git? — Deep dive into version control commands.
• What Is SSH? — Use terminal commands to connect to remote servers.
• Understanding package.json — Every npm command interacts with this file.
• What Are Environment Variables? — export and .env files explained.

FAQ