[CentOS] list installed packaged, without formatting overhead

Hi all,

In order to make the same installation on two servers where all was 
installed via yum/rpm, I want to dump a list of all installed packages 
on the first server.

My problem is if I just "yum list installed", some weird formatting 
prints packages information on 2 lines...
I have to

   # yum list installed | awk '{print $1}' \
       | grep -v '@' | grep -vE '^[0-9]'

Is there a cleaner way?
   # rpm -aq
Is not OK because it includes version in a way it's more hard to parse 
just the package name.

Thank you.

-- 
RMA.