We can use the **Readline module** for a line-by-line reading of any input stream. The module can be made available as follows:

```
var readline = require('readline');
```

The Readline module comes with several methods to interact with users. The process is very simple. In order to interact with any user, we must first create an interface initializing input and output stream. 
 

# Syntax
```
readline.createInterface(input, output, completer) 
```
To create an interface:
```
var rl = readline.createInterface(
     process.stdin, process.stdout);
```

The method `createInterface()` takes two parameters -- the input stream and output stream -- to create a readline interface. The third parameter is used for autocompletion and is mostly initialized as `NULL`. For example, one may want to access the tab, similar to how we might press the `TAB` key to complete a give string. 

> As input parameter, `createInterface` uses  `process.stdin`. As output parameter, `createInterface` uses  `process.stdout`.








# Code
The following code explains how a user can interact. The terminal prompts a question, "How do you feel today?". The users enter their response. The program notes the response and terminal then responds with "Have a great day!". The program is terminated since `readline` is closed in line 11. 

// call readline
var readline = require('readline');
 
var rl = readline.createInterface(process.stdin, process.stdout);
rl.question("How do you feel today? ", function(answer) {
  // ask a question to interact with user. 

  console.log("Have a great day!");
 
  // close the program
  rl.close();
});

What is readline module createInterface() in Node.js?

Node.js's Readline module enables line-by-line input stream reading, using `readline.createInterface()` with input and output streams for user interaction.