Node.js — Command Line

process.argv

// script.js
const args = process.argv.slice(2);
console.log('Arguments:', args);

node script.js hello world
# Arguments: [ 'hello', 'world' ]

Command-Line Arguments

const args = process.argv.slice(2);
const command = args[0];
const options = args.slice(1);

switch (command) {
    case 'greet':
        console.log(`Hello, ${options[0]}!`);
        break;
    case 'add':
        console.log(options.reduce((a, b) => Number(a) + Number(b), 0));
        break;
}

Environment Variables

console.log(process.env.NODE_ENV);
console.log(process.env.HOME);

NODE_ENV=production node app.js

Process Object

Property	Description
process.argv	Command-line arguments
process.env	Environment variables
process.cwd()	Current directory
process.exit()	Exit process
process.version	Node.js version

Mini Practice

1. Access command-line arguments
2. Use environment variables
3. Build a simple CLI tool
4. Handle different commands

Up Next

Continue with Modules — CommonJS and ES Modules.