Child Process Operations

/**
 * Execute a shell command in a new process
 * @param command - Command string to execute
 * @param options - Execution options
 * @returns Promise resolving to stdout string
 */
function exec(command, options): Promise<string>;

/**
 * Execute a file directly without shell interpretation
 * @param file - Path to executable file
 * @param args - Array of arguments to pass to executable
 * @param options - Execution options
 * @returns Promise resolving to stdout string
 */
function execFile(file, args, options): Promise<string>;

const { exec, execFile } = require('mz/child_process');

// Execute shell commands
async function runCommands() {
  try {
    // Get Node.js version
    const nodeVersion = await exec('node --version');
    console.log('Node version:', nodeVersion.trim());
    
    // List files in current directory
    const files = await exec('ls -la');
    console.log('Directory contents:', files);
    
    // Execute with options
    const result = await exec('echo "Hello World"', {
      cwd: '/tmp',
      env: { ...process.env, CUSTOM_VAR: 'value' }
    });
    console.log('Command output:', result);
    
  } catch (error) {
    console.error('Command failed:', error.message);
    // Error object contains additional properties:
    // - error.code: exit code
    // - error.signal: signal that terminated the process
    // - error.stdout: stdout output
    // - error.stderr: stderr output
  }
}

// Execute files directly
async function runExecutable() {
  try {
    // Execute Node.js directly with arguments
    const output = await execFile('node', ['--version']);
    console.log('Node version:', output.trim());
    
    // Execute with options
    const result = await execFile('/bin/echo', ['Hello', 'World'], {
      cwd: '/tmp'
    });
    console.log('Echo output:', result);
    
  } catch (error) {
    console.error('Execution failed:', error);
  }
}

// Callback support is still available
exec('pwd', (err, stdout, stderr) => {
  if (err) {
    console.error('Error:', err);
  } else {
    console.log('Current directory:', stdout.trim());
  }
});

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

async function handleCommandErrors() {
  try {
    await exec('nonexistent-command');
  } catch (error) {
    console.log('Exit code:', error.code);
    console.log('Signal:', error.signal);
    console.log('Stdout:', error.stdout);
    console.log('Stderr:', error.stderr);
  }
}

interface ExecOptions {
  /** Current working directory for the command */
  cwd?: string;
  /** Environment variables */
  env?: object;
  /** Character encoding for stdout/stderr */
  encoding?: string;
  /** Shell to execute the command with (exec only) */
  shell?: string;
  /** Timeout in milliseconds */
  timeout?: number;
  /** Largest amount of data in bytes allowed on stdout/stderr */
  maxBuffer?: number;
  /** Kill signal to use when timeout is reached */
  killSignal?: string;
  /** User ID to run the command as */
  uid?: number;
  /** Group ID to run the command as */
  gid?: number;
  /** Whether to run in detached mode */
  detached?: boolean;
  /** Whether to create new console window (Windows only) */
  windowsVerbatimArguments?: boolean;
}