Ignore already-installed packages when multiple RPMs are passed

[Toralf Lund <toralf procaptura com>]

Something I've been wondered about for as long as I've been using RPM:

Is there a way I can get rpm -U or similar to simply skip any package 
where the same ore a newer version is installed, but go ahead and 
install the ones that need upgrade or first-time installation, rather 
than simply exiting when the situation occurs?

What I'm looking for is in a sense a cross between '--replacepkgs' and 
the default behaviour, or between 'rpm -U' and 'rpm -F', depending on 
the way you look at it...

Just so everyone understands what I mean, assume that the comple list of 
rpms installed (rpm -qa output) is:

a-1-1
b-1-2
c-1-2

I want to be able to say

rpm <something> a-1-2.<arch>.rpm b-1-1.<arch>.rpm c-1-2.<arch>.rpm 
d-1-1.<arch>.rpm
and end up with

a-1-2
b-1-2
c-1-2
d-1-1

The command should not reinstall c-1-2, or downgrade b to version 1-1.


- Toralf