remove_redundant_ami.sh

#!/bin/bash
set -euo pipefail

usage () {
  echo "script syntax:    -a       AWS account nickname
                  -r       AWS region
                  -h       This help text";
}

options=':a:r:h'
while getopts $options option
do
    case $option in
        a  ) AWS_PROFILE_NAME=$OPTARG;;
        r  ) AMI_REGIONS=$OPTARG;;
        h  ) usage; exit;;
        \? ) echo "ERROR: Unknown option: -$OPTARG" >&2; exit 1;;
        :  ) echo "ERROR: Missing argument value for -$OPTARG" >&2; exit 1;;
    esac
done

shift $(($OPTIND - 1))

if [[ -z "$AWS_PROFILE_NAME" ]]; then
  echo "ERROR: Missing argument - please provide the AWS account's profile name."
  exit 1
fi

AMI_REGIONS=${AMI_REGIONS:-"us-east-1 eu-west-1 ap-southeast-2"}

for region in $AMI_REGIONS; do
  images=$(aws ec2 describe-images --profile $AWS_PROFILE_NAME --region $region --owners <ID> --output text --query 'Images[*].ImageId')
  for i in $images; do
    instances=$(aws ec2 describe-instances --profile $AWS_PROFILE_NAME --region $region --filters "Name=image-id,Values=$i" | jq '.Reservations | has(0)')
    if [ "$instances" == "true" ]; then
      echo "$i has an instance and will not be deregistered"
    else
      echo "$i does not have an instance and will be deregistered"
      # Run describe-images command (OSX/Linux/UNIX) using the ID of the unused AMI (see the Audit section for getting the unused AMIs metadata) as identifier to return the ID of the EBS snapshot associated with the selected image
      #snapshot=$(aws ec2 describe-images --profile $AWS_PROFILE_NAME --region $region --image-ids $i --output text --query 'Images[*].BlockDeviceMappings[*].Ebs.SnapshotId')

      # Once you identified the AMI snapshot ID run deregister-image command (OSX/Linux/UNIX) using the image ID as identifier to deregister the selected AMI (the command does not produce an output)
      #aws ec2 deregister-image --profile $AWS_PROFILE_NAME --region $region --image-id $i

      # Finally, run delete-snapshot command (OSX/Linux/UNIX) using the ID returned at step no. 2 as identifier, to complete the removal/cleanup process by deleting the snapshot associated with the selected image (if successful, the command does not return an output)
      #aws ec2 delete-snapshot --profile $AWS_PROFILE_NAME --region $region --snapshot-id $snapshot
    fi
  done
  
  #snapshot=$(aws ec2 describe-snapshots --profile stage --region us-east-1 --filters "Name=owner-id,Values=<ID>" --output text --query '[Snapshots[*].Description]')
  #regex=".*for (ami-.*) from.*"
  # ${BASH_REMATCH[1]}
  # Set images again against no owner-id
  # Then check if snapshot is part of that list
done