old_contents: var redis      = require('redis');
  var SerialPort = require('serialport');
  var fs = require('fs');
  
  var files = fs.readdirSync('/dev/');
  console.log('files=<',files,'>');
  files.forEach(function(file) {
    console.log('file=<',file,'>');
  });
  
  
  
  var subscriber = redis.createClient(6379, 'localhost'); 
  subscriber.subscribe('/dbc/webui2uart');
  subscriber.on("message", function(channel, message) {
    console.log('message=<',message,'>');
  });
  
  var serialPort = new SerialPort("/dev/ttyS0", {
   baudrate: 112500
  });
  
  serialPort.on("open", function () {
    console.log('open');
   });
  
  serialPort.on('data', function(data) {
    console.log('received data =<',data,'>');
  });
  
  serialPort.on('error', function(err) {
    console.log('err =<',err,'>');
  });
  
new_contents: var redis      = require('redis');
  var SerialPort = require('serialport');
  var fs = require('fs');
  
  var files = fs.readdirSync('/dev/');
  console.log('files=<',files,'>');
  files.forEach(function(file) {
    //console.log('file=<',file,'>');
    if(file.startsWith('ttyUSB')) {
      console.log('file=<',file,'>');
    }
  });
  
  
  
  var subscriber = redis.createClient(6379, 'localhost'); 
  subscriber.subscribe('/dbc/webui2uart');
  subscriber.on("message", function(channel, message) {
    console.log('message=<',message,'>');
  });
  
  var serialPort = new SerialPort("/dev/ttyS0", {
   baudrate: 112500
  });
  
  serialPort.on("open", function () {
    console.log('open');
   });
  
  serialPort.on('data', function(data) {
    console.log('received data =<',data,'>');
  });
  
  serialPort.on('error', function(err) {
    console.log('err =<',err,'>');
  });
  
subject: Update app.js