exec for running shell commands in Node.js - Mini Project: Build & Apply

Using exec to Run Shell Commands in Node.js

📖 Scenario: You are building a simple Node.js script that runs a shell command to list files in a folder. This is useful when you want your program to interact with the system shell to get information or run tools.

🎯 Goal: Create a Node.js script that uses exec from the child_process module to run the ls -l command and handle its output.

📋 What You'll Learn

Import the exec function from the child_process module

Create a variable command with the exact string ls -l

Use exec to run the command variable

Handle the callback to print the command output or error

💡 Why This Matters

🌍 Real World

Running shell commands from Node.js scripts helps automate system tasks, gather system info, or run external tools.

💼 Career

Many backend developers use exec to integrate system commands or scripts into their Node.js applications.

1

Import exec from child_process

Write a line to import exec from the child_process module using destructuring assignment.

Node.js

// Your code here

Need a hint?

Use const { exec } = require('child_process'); to import exec.

2

Create the command variable

Create a variable called command and set it to the string 'ls -l'.

Node.js

const { exec } = require('child_process');
// Your code here

Need a hint?

Use const command = 'ls -l'; to store the shell command.

3

Run the command with exec

Use exec to run the command variable. Provide a callback with parameters error, stdout, and stderr.

Node.js

const { exec } = require('child_process');
const command = 'ls -l';
// Your code here

Need a hint?

Call exec(command, (error, stdout, stderr) => { ... }) to run the command.

4

Handle output and errors

Inside the exec callback, add code to check if error exists. If yes, return early. Otherwise, log stdout to the console.

Node.js

const { exec } = require('child_process');
const command = 'ls -l';

exec(command, (error, stdout, stderr) => {
  // Your code here
});

Need a hint?

Use if (error) { return; } to stop on error, then console.log(stdout); to show output.