core/node_modules/macaddress/test.js

var macaddress = require('./index');

var sync = macaddress.one(function (err, mac) {
  if (err || !/[a-f0-9]{2}(:[a-f0-9]{2}){5}/.test(mac)) {
    throw err || mac;
  }
  console.log("Mac address for this host: %s", mac);  
});
console.log("Mac address obtained synchronously: %s", sync);

macaddress.all(function (err, all) {
  if (err) {
    throw err;
  }
  console.log(JSON.stringify(all, null, 2));
});

console.log(JSON.stringify(macaddress.networkInterfaces(), null, 2));