> Has anyone ever had yum on Centos (5) stop expanding the $releasever
> variable in the repo config?
>
> I am being asked to fix one which has just started doing this,
> supposedly without anyone having done anything to make it so (no, I
> don't believe that).
Someone has upgraded the yum or $distro-release packages...
As John said, check distroverpkg in /etc/yum.conf, and see what
"foo-release" files you can find in /etc.
