def linux_get_string_mac_address(iface_name):
    """
    It returns the MAC from an interface in Linux platforms as a string.
    """
    address_path = '/sys/class/net/%s/address' % iface_name
    fd = open(address_path, 'r')
    mac_address = fd.read()
    fd.close()
    return mac_address.strip()