Node.JS demo program

Let's create some NODE.JS application that will communicate with active terminal and make it runnable from Linux bash shell...

  • Install Node.JS

  • Create folder for your project and add file package.json

  • Open package.json with text editor and add minimum required, then save it

  • Position to project folder from console and execute following to install required lib

      npm install ws --save
      npm install mem-cache --save

Create index.js in project folder and add code shown at the end of the page.

Code can be executed as bash shell script simply by calling ./index.js or with Node.JS itself by executing from command line with node index.js.

index.js file
#!/usr/bin/env node

const WebSocket = require('ws');
const Cache = require('mem-cache');

var cache = new Cache();
var ws = new WebSocket('ws://localhost:5250')

 * Store request into cache and make remote request
function request(req, callback) {

  // store request into cache for 30 seconds
  cache.set(req.rid, {callback : callback}, 30000);

  // send request to GreenScreens Native Terminal

 * Receive response from terminal and process data
ws.on('message', function(resp, raw) {

   // parse received text data into JSON
   let data = JSON.parse(resp);

   // take rid from response and look into cache
   let cdata = cache.get(data.rid);

   // if request stored into cache and have callback function, execute it
   if (cdata && typeof cdata.callback === 'function') {

 * Signal when connection established
ws.on('open', function open() {

    // prepare A-HLL API command
    let req = {"cmd": "echo", "rid":};

    // send A-HLL command to terminal and attach response handler
    request(req, function(resp){
      console.log(`Response arrived from terminal for request ID: ${resp.rid}`);