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

[Barry Brimer]

>>>>>>>> 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?
>>>>> Dumb question: in /etc/sysconfig/network-scripts, do the ifcfg-* have
>>>>> HWADDRs?

biosdevname is in RHEL 6.1 and thus is in CentOS 6.1 but is only enabled 
by default for certain pieces of Dell hardware that could gain the most 
benefit from it.  If you are running 6.1 and want to force biosdevname to 
be used, you can pass biosdevname=1 on the kernel line in the grub config, 
but don't plan on switching between the two.  For those with paid RHN 
access, this is explained further in 
https://access.redhat.com/kb/docs/DOC-53612

Barry