For private IP address:
aws ec2 describe-instances --instance-ids i-b78a096f | grep PrivateIpAddress | head -1 | awk -F ":" '{print $2}' | sed 's/[",]//g'
For public IP address:
aws ec2 describe-instances --instance-ids i-b78a096f | grep PublicIpAddress | awk -F ":" '{print $2}' | sed 's/[",]//g'