Jassif Team Institution

// Process identification
console.log('Process ID (PID):', process.pid);

// Platform information
console.log('Platform:', process.platform);
console.log('Node.js version:', process.version);

// Memory usage (in bytes)
console.log('Memory usage:', process.memoryUsage());

// Command line arguments
console.log('Arguments:', process.argv);

// Exit with success (status code 0)
process.exit();

// Or explicitly
process.exit(0);

// Exit with error (status code 1)
process.exit(1);

// Run cleanup before exiting
process.on('beforeExit', (code) => {
  console.log('About to exit with code:', code);
});

// Handle Ctrl+C
process.on('SIGINT', () => {
console.log('\nGot SIGINT. Press Control-D to exit.');
// Perform cleanup if needed
process.exit(0);

process.on('SIGTERM', () => {
  console.log('Received SIGTERM. Cleaning up...');
  // Perform cleanup if needed
  process.exit(0);
});

process.on('SIGTERM', () => {
  console.log('Received SIGTERM. Cleaning up...');
  server.close(() => {
    console.log('Server closed');
    process.exit(0);
  });
});

process.on('uncaughtException', (err) => {
  console.error('Uncaught Exception:', err);
  // Perform cleanup if needed
  process.exit(1); // Exit with error
});

npm install -g pm2

# Start an application
pm2 start app.js

# List all running applications
pm2 list

# Monitor resources
pm2 monit

# View application logs
pm2 logs

# Stop an application
pm2 stop app_name

# Restart an application
pm2 restart app_name

# Delete an application from PM2
pm2 delete app_name

// ecosystem.config.js
module.exports = {
  apps: [{
    name: 'my-app',
    script: 'app.js',
    instances: 'max',
    autorestart: true,
    watch: false,
    max_memory_restart: '1G',
    env: {
      NODE_ENV: 'development',
    },
    env_production: {
      NODE_ENV: 'production',
    }
  }]
};

// Get a specific environment variable
const apiKey = process.env.API_KEY;

// Set a default value if not defined
const port = process.env.PORT || 3000;

// Check if running in production
const isProduction = process.env.NODE_ENV === 'production';

// List all environment variables
console.log('Environment variables:', process.env);

# Install dotenv package
npm install dotenv

// Load environment variables from .env file
require('dotenv').config();

// Now you can access variables from .env
console.log('Database URL:', process.env.DATABASE_URL);

const { exec } = require('child_process');

exec('ls -la', (error, stdout, stderr) => {
  if (error) {
    console.error(`Error: ${error.message}`);
    return;
  }
  if (stderr) {
    console.error(`stderr: ${stderr}`);
    return;
  }
  console.log(`Output: ${stdout}`);
});

const { spawn } = require('child_process');

// Better for large data output
const child = spawn('find', ['/', '-type', 'f']);
child.stdout.on('data', (data) => {
  console.log(`Found file: ${data}`);
});
child.stderr.on('data', (data) => {
  console.error(`Error: ${data}`);
});
child.on('close', (code) => {
  console.log(`Child process exited with code ${code}`);
});

// Get memory usage in MB
function getMemoryUsage() {
  const used = process.memoryUsage();
  return {
    rss: `${Math.round(used.rss / 1024 / 1024 * 100) / 100} MB`,
    heapTotal: `${Math.round(used.heapTotal / 1024 / 1024 * 100) / 100} MB`,
    heapUsed: `${Math.round(used.heapUsed / 1024 / 1024 * 100) / 100} MB`,
    external: `${Math.round(used.external / 1024 / 1024 * 100) / 100} MB`
  };
}

// Monitor memory usage every 5 seconds
setInterval(() => {
  console.log('Memory usage:', getMemoryUsage());
}, 5000);

const startUsage = process.cpuUsage();

// Do some CPU-intensive work
for (let i = 0; i < 1000000000; i++) {}

const endUsage = process.cpuUsage(startUsage);
console.log('CPU usage (user):', endUsage.user / 1000, 'ms');
console.log('CPU usage (system):', endUsage.system / 1000, 'ms');