AWS EC2: Find unused security groups by region

aws-ec2-find-unused-security-groups-by-region.sh

#!/bin/bash

# exit when the command fails
set -o errexit;

# exit when try to use undeclared var
set -o nounset;

region=us-east-1

for securityGroup in $(aws ec2 describe-security-groups --query 'SecurityGroups[*].GroupId' --region $region --output text); do	
	if [[ `aws ec2 describe-network-interfaces --filters Name=group-id,Values=$securityGroup --region $region --output json | grep -c NetworkInterfaceId` -eq 0 ]]; then
		echo $securityGroup;
	fi;
done;