Here is a bash command that will give you the list of IP addresses of your instances in an AutoScaling group.
for ID in $(aws autoscaling describe-auto-scaling-instances --region us-east-1 --query AutoScalingInstances[].InstanceId --output text);
do
aws ec2 describe-instances --instance-ids $ID --region us-east-1 --query Reservations[].Instances[].PublicIpAddress --output text
done
You might want to adjust the region and to filter per AutoScaling group if you have several of them.