Changing file prefix in bulk in Linux

Linux IT
find . -name pg-\*|awk '{a=$1;sub(/\pg-/,"ppas-",a);printf "mv %-100s %s\n",$1,a}'>xyz


This command will change the file names prefix from one to another. For example, I have files in current (and sub) directory as pg-aaa.x pg-bbb.x and I want to change these to ppas-aaa.x ppas-bbb.x. The commands will be directed to file xyz. Source it to run the actual commands. i.e.
. xyz