runTesselasChild

 var exec = require('child_process').exec,
     ls;

  var stdout = '';
  var stderr = '';

 ls = exec('tessel run mifareClassic.js', function (error, stdout, stderr) {
   if (error) {
     console.log(error.stack);
     console.log('Error code: '+error.code);
     console.log('Signal received: '+error.signal);
   }
   console.log('test');
   console.log('Child Process STDOUT: '+stdout);
   console.log('Child Process STDERR: '+stderr);
 });

 ls.on('exit', function (code) {
   console.log('Child process exited with exit code '+code);
 });

   ls.stdout.on('data', function(buf) {
   // console.log('[STR] stdout "%s"!', String(buf));
    if(buf.search("Ready") == 0) console.log('swap your card');
    if(buf.search("UID") == 0) console.log(String(buf).substring(4));
    if(buf.search("Old") == 0) console.log('old %s',String(buf).substring(8));
    if(buf.search("New") == 0) console.log('new %s',String(buf).substring(13));
    //stdout += buf;
  });
  ls.stderr.on('data', function(buf) {
   // console.log('[STR] stderr "%s"', String(buf));
    stderr += buf;
  });
  ls.on('close', function(code) {
    console.log('[END] code', code);
    console.log('[END] stdout "%s"', stdout);
    console.log('[END] stderr "%s"', stderr);
  });