On Apr 1, 2009, at 1:40 PM, Eric Shubert wrote:

>
> yum list | grep openmpi     # (checking to see if it is installed)
> yum list | grep lam         # (checking to see if it is installed)

I think this will only find packages which were installed by yum.

If you download an RPM to a machine (wget, scp, etc) and install it  
using the 'rpm' command, it will not be found by 'yum list'.  Seems  
like a big oversight, but that was my experience on some RHEL5  
machines I was an admin for.  (I used RHEL4 more, and it still used  
up2date.  yum is much superior but I didn't have as much experience  
with it.)