code: function getInterfaceMAC (device) {
    if (process.platform === 'darwin' || process.platform === 'linux') {
      let output
      try {
        output = cp.execSync(quote(['ifconfig', device]), { stdio: 'pipe' }).toString()
      } catch (err) {
        return null
      }
  
      const address = MAC_ADDRESS_RE.exec(output)
      return address && normalize(address[0])
    } else if (process.platform === 'win32') {
      console.error('No windows support for this method yet - PR welcome!')
    }
  }
docs: Returns currently-set MAC address of given interface. This is distinct from the
  interface's hardware MAC address.
  @return {string}