AWS:RDS:List all DBs by CA Certificate

account=$(aws iam list-account-aliases | jq -r '.AccountAliases.[]' ); 
regions | while read r; 
do 
    aws rds describe-db-instances --region=$r 2>/dev/null |\  
    jq -r '.DBInstances[] | ( [ .DBInstanceIdentifier , .Engine , .AvailabilityZone , .CACertificateIdentifier ] | @csv )' |\ 
    awk '{ print "'$account','$r',"$0 }'; 
done