def update_vlan_file ():
        hardware_configuration = ["SMI0", "SMI1"]  # First two lines of file
        hardware_configuration += readvtu("1")     # Append hardware config
        try:
                f = open('/tmp/vlan.config', 'w')
        except IOError as e:
                return "Could not update Vlan Configuration\n"
        map(f.write, hardware_configuration)
    f.close()