The os module in Node.js provides operating system-related utility methods and properties. It is a core module, meaning it comes bundled with Node.js and doesn't require separate installation. The os module helps you interact with the underlying operating system in a platform-independent way, making it useful for tasks such as retrieving system information or managing system-specific settings.

Key Features of the os Module

1. System Information: Retrieve information about the operating system, such as hostname, platform, and architecture.
2. System Resources: Access details about system memory, CPU usage, and more.
3. Temporary Directory: Get the path to the system's temporary directory.
4. Network Interfaces: List network interfaces and their addresses.

Commonly Used Methods and Properties

**1. os.platform()

Returns a string identifying the operating system platform.

Example:

const os = require('os');

console.log(os.platform()); // 'linux', 'darwin', 'win32', etc.

**2. os.type()

Returns the operating system name as a string.

Example:

const os = require('os');

console.log(os.type()); // 'Linux', 'Darwin', 'Windows_NT'

**3. os.arch()

Returns the CPU architecture of the operating system.

Example:

const os = require('os');

console.log(os.arch()); // 'x64', 'arm', etc.

**4. os.release()

Returns the operating system version.

Example:

const os = require('os');

console.log(os.release()); // '5.10.0-9-amd64', '20.4.0', etc.

**5. os.hostname()

Returns the hostname of the operating system.

Example:

const os = require('os');

console.log(os.hostname()); // 'my-computer'

**6. os.cpus()

Returns an array of objects containing information about each CPU/core installed.

Example:

const os = require('os');

const cpus = os.cpus();
cpus.forEach((cpu, index) => {
  console.log(`CPU ${index}: ${cpu.model}`);
});

Output:

CPU 0: Intel(R) Core(TM) i7-8565U CPU @ 1.80GHz
CPU 1: Intel(R) Core(TM) i7-8565U CPU @ 1.80GHz
...

**7. os.totalmem()

Returns the total amount of system memory in bytes.

Example:

const os = require('os');

console.log(os.totalmem()); // 17179869184 (bytes)

**8. os.freemem()

Returns the amount of free system memory in bytes.

Example:

const os = require('os');

console.log(os.freemem()); // 8589934592 (bytes)

**9. os.uptime()

Returns the system uptime in seconds.

Example:

const os = require('os');

console.log(os.uptime()); // 123456 (seconds)

**10. os.tmpdir()

Returns the path to the system's temporary directory.

Example:

const os = require('os');

console.log(os.tmpdir()); // '/tmp' on UNIX-like systems or 'C:\Users\<username>\AppData\Local\Temp' on Windows

**11. os.networkInterfaces()

Returns an object containing network interfaces and their addresses.

Example:

const os = require('os');

const networkInterfaces = os.networkInterfaces();
console.log(networkInterfaces);
/* Example Output:
{
  lo: [
    { address: '127.0.0.1', family: 'IPv4', internal: true, mac: '00:00:00:00:00:00', netmask: '255.0.0.0' }
  ],
  eth0: [
    { address: '192.168.1.100', family: 'IPv4', internal: false, mac: '00:11:22:33:44:55', netmask: '255.255.255.0' }
  ]
}
*/

Use Cases

1. System Monitoring: Collect information about the operating system and hardware to monitor system performance and health.
2. Cross-Platform Applications: Adjust application behavior based on the underlying operating system or architecture.
3. Resource Management: Access system memory and CPU details to manage resource-intensive applications.
4. Temporary Files: Use the system's temporary directory for storing temporary files and data.

Example Use Case

System Resource Report

You might create a simple script to log system resources:

const os = require('os');

console.log('Operating System Information:');
console.log(`Platform: ${os.platform()}`);
console.log(`Architecture: ${os.arch()}`);
console.log(`OS Version: ${os.release()}`);
console.log(`Hostname: ${os.hostname()}`);
console.log(`Total Memory: ${os.totalmem() / (1024 * 1024 * 1024)} GB`);
console.log(`Free Memory: ${os.freemem() / (1024 * 1024 * 1024)} GB`);
console.log(`Uptime: ${os.uptime()} seconds`);
console.log(`Temporary Directory: ${os.tmpdir()}`);

console.log('Network Interfaces:');
console.log(os.networkInterfaces());

Summary

• System Information: Methods like os.platform(), os.type(), os.arch(), os.release(), and os.hostname() provide details about the operating system.
• System Resources: Methods such as os.cpus(), os.totalmem(), os.freemem(), and os.uptime() give insights into system performance and resource usage.
• Temporary Directory: os.tmpdir() provides the path to the system's temporary directory.
• Network Interfaces: os.networkInterfaces() lists network interfaces and their addresses.