yum list installed command shows a listing of the packages actually installed in the system.
# su -c "yum list installed" Installed Packages GConf2.i386 2.14.0-1 installed GConf2-devel.i386 2.14.0-1 installed GFS.i386 6.1.5-0.FC5.1 installed GFS-kernel-smp.i686 2.6.15.1-5.FC5.33 installed .... [many others]