OS Module

🖥️ Node.js OS Module: Your Computer’s Health Report

The Story of a Curious Doctor

Imagine you’re a doctor who can check on your computer’s health anytime! The os module in Node.js is like your medical toolkit — it tells you everything about your computer: its name, how much energy (memory) it has, how hard it’s working, and where it keeps important things.

Let’s explore this toolkit together!

📚 What is the OS Module?

The os module is a built-in part of Node.js that gives you information about your computer’s operating system (like Windows, Mac, or Linux).

Think of it like asking your computer:

• “What’s your name?”
• “How are you feeling today?”
• “Where do you keep your stuff?”

Getting Started

const os = require('os');
// Now you have your medical toolkit ready!

That’s it! One line, and you’re ready to explore.

🔍 OS Identification: Who Are You, Computer?

Just like people have names and personalities, computers have identities too!

What Type of Computer?

const os = require('os');

// What operating system?
console.log(os.type());
// Output: "Linux", "Darwin" (Mac), or "Windows_NT"

// What's your platform?
console.log(os.platform());
// Output: "linux", "darwin", or "win32"

Real-World Example:

const myOS = os.platform();

if (myOS === 'win32') {
  console.log("You're on Windows! 🪟");
} else if (myOS === 'darwin') {
  console.log("You're on Mac! 🍎");
} else {
  console.log("You're on Linux! 🐧");
}

Computer’s Version & Details

// Operating system version
console.log(os.release());
// Output: "10.0.19041" (Windows) or "5.4.0" (Linux)

// Computer's architecture (32-bit or 64-bit)
console.log(os.arch());
// Output: "x64" or "arm64"

// Computer's network name
console.log(os.hostname());
// Output: "my-awesome-laptop"

graph TD
    A["os.type"] --> B["Linux / Darwin / Windows_NT"]
    C["os.platform"] --> D["linux / darwin / win32"]
    E["os.arch"] --> F["x64 / arm64 / ia32"]
    G["os.hostname"] --> H["Your Computer Name"]

💪 System Resource Information: How Strong Is Your Computer?

Now let’s check your computer’s muscles and energy!

Memory: How Much Brain Power?

const os = require('os');

// Total memory (RAM) in bytes
const totalMemory = os.totalmem();
console.log('Total Memory:', totalMemory);

// Free memory available right now
const freeMemory = os.freemem();
console.log('Free Memory:', freeMemory);

Making It Human-Readable:

// Convert bytes to gigabytes
const toGB = (bytes) => {
  return (bytes / 1024 / 1024 / 1024).toFixed(2);
};

console.log(`Total: ${toGB(os.totalmem())} GB`);
console.log(`Free: ${toGB(os.freemem())} GB`);
// Output: "Total: 16.00 GB"
// Output: "Free: 8.45 GB"

CPU: The Computer’s Brain

// Get all CPU cores
const cpus = os.cpus();

// How many cores?
console.log('CPU Cores:', cpus.length);
// Output: "CPU Cores: 8"

// CPU model name
console.log('CPU Model:', cpus[0].model);
// Output: "Intel(R) Core(TM) i7-9700K"

// CPU speed
console.log('Speed:', cpus[0].speed, 'MHz');
// Output: "Speed: 3600 MHz"

System Uptime: How Long Have You Been Awake?

// Seconds since computer started
const uptime = os.uptime();

// Convert to hours and minutes
const hours = Math.floor(uptime / 3600);
const minutes = Math.floor((uptime % 3600) / 60);

console.log(`Computer awake: ${hours}h ${minutes}m`);
// Output: "Computer awake: 5h 23m"

graph TD
    A["System Resources"] --> B["Memory"]
    A --> C["CPU"]
    A --> D["Uptime"]
    B --> E["totalmem - Total RAM"]
    B --> F["freemem - Available RAM"]
    C --> G["cpus - Core Details"]
    D --> H["uptime - Time Since Boot"]

📁 System Paths and Identity: Where’s Everything?

Every computer has special folders. The OS module tells you exactly where they are!

Home Directory: Your Personal Space

// Where is the user's home folder?
console.log(os.homedir());
// Windows: "C:\\Users\\John"
// Mac/Linux: "/home/john"

Temp Directory: The Scratch Paper Folder

// Where to store temporary files?
console.log(os.tmpdir());
// Windows: "C:\\Users\\John\\AppData\\Local\\Temp"
// Mac/Linux: "/tmp"

Why is this useful?

const path = require('path');
const os = require('os');

// Create a temp file path
const tempFile = path.join(
  os.tmpdir(),
  'my-temp-file.txt'
);
console.log(tempFile);
// Output: "/tmp/my-temp-file.txt"

User Info: Who’s Using This Computer?

const userInfo = os.userinfo();

console.log('Username:', userInfo.username);
console.log('Home Dir:', userInfo.homedir);
console.log('User ID:', userInfo.uid);
// Output:
// Username: john
// Home Dir: /home/john
// User ID: 1000

Network Interfaces: How You Connect

const networks = os.networkInterfaces();

// See all network connections
for (const [name, interfaces] of
     Object.entries(networks)) {
  console.log(`\n${name}:`);
  interfaces.forEach(net => {
    console.log(`  ${net.family}: ${net.address}`);
  });
}
// Output:
// eth0:
//   IPv4: 192.168.1.100
//   IPv6: fe80::1

graph TD
    A["System Paths"] --> B["homedir"]
    A --> C["tmpdir"]
    A --> D["userinfo"]
    B --> E[User's Home Folder]
    C --> F["Temporary Files Location"]
    D --> G["Username & UID"]

🎯 Quick Reference Summary

🌟 Real-World Mini Project

Let’s build a System Health Report:

const os = require('os');

function getHealthReport() {
  const toGB = b => (b/1024/1024/1024).toFixed(2);
  const toHours = s => (s/3600).toFixed(1);

  return {
    computer: os.hostname(),
    os: os.type(),
    platform: os.platform(),
    architecture: os.arch(),
    cpuCores: os.cpus().length,
    totalMemoryGB: toGB(os.totalmem()),
    freeMemoryGB: toGB(os.freemem()),
    uptimeHours: toHours(os.uptime()),
    homeDir: os.homedir(),
    tempDir: os.tmpdir(),
    user: os.userinfo().username
  };
}

console.log(getHealthReport());

🎉 You Did It!

Now you can:

• ✅ Identify any operating system
• ✅ Check computer resources (memory, CPU)
• ✅ Find important system paths
• ✅ Get user information

The OS module is your window into the computer’s soul. Use it wisely to build smarter applications that adapt to any system!

Remember: The OS module requires no installation — it’s built right into Node.js. Just require('os') and you’re ready to explore!