[CentOS] 6.x - find interface with link up

In earlier versions 'mii-tool' would iterate over interfaces and show
which have link up.   In 6.x it wants an interface as a parameter.
What is the appropriate way to find which of some number of of
interfaces are connected?   Better yet, what is the least typing to
get the mac addresses of those interfaces?

-- 
  Les Mikesell
    lesmikesell at gmail.com