node-cli-example.run

#!/usr/bin/env node

const readline = require("readline");

// instantiate a readline
const cli = readline.createInterface({
    input: process.stdin,
    output: process.stdout,
    prompt: "\n> ",
});

// prompts the user and waits for input
cli.prompt();

// listen for user input
cli.on("line", (line) => {
    const input = line.trim();

    switch (input) {
        case "env": {
            for (const variable in process.env) {
                console.log(`${variable}: ${process.env[variable]}`);
            }

            break;
        }
        case "quit": {
            console.log("Bye!");

            process.exit(0);
        }
        case "help":
        default: {
            console.log(
                "\nCommands available\n\
--------------------------------------\n\n\
env      display environment variables\n\n\
quit     quit the CLI\
"
            );
        }
    }

    cli.prompt();
});