compare packages between two RHEL systems

#generate package list on hostname1
rpm -qa --qf "%{NAME}\n" > hostname1.rpm.txt
cat ./hostname1.rpm.txt | sort | uniq > ./hostname1_final.rpm.txt

#generate package list on hostname2
rpm -qa --qf "%{NAME}\n" > hostname2.rpm.txt
cat ./hostname2.rpm.txt | sort | uniq > ./hostname2_final.rpm.txt

#you want the difference between systems - show diffs on the right and trim leading whitespace
sdiff ./hostname1.rpm.txt ./hostname2.rpm.txt | grep '>' | sed -e 's/^[> \t]*//'


#you want the difference between systems - show diffs on the left and trim trailing whitespace
sdiff ./hostname1.rpm.txt ./hostname2.rpm.txt | grep '<' | sed -e 's/[ \t<]*$//'