Find self-owned AMI's which are not used by any instances or launch configurations in a region

find-unused-amis

#!/bin/bash

# Find self-owned AMI's which are not used by any instances or launch configurations in the default region.
comm -23 \
  <(aws ec2 describe-images --owner self --query 'Images[].[ImageId]' --output text | sort) \
  <((aws ec2 describe-instances --query 'Reservations[].Instances[].[ImageId]' --output text;
    aws autoscaling describe-launch-configurations --query 'LaunchConfigurations[].[ImageId]' --output text) | sort -u)

find-unused-amis-with-details

#!/bin/bash

# Find self-owned AMI's which are not used by any instances or launch configurations in the default region.
# Output with details in descending order of name and creation date.
aws ec2 describe-images --image-ids \
  $(comm -23 \
    <(aws ec2 describe-images --owner self --query 'Images[].[ImageId]' --output text | sort) \
    <((aws ec2 describe-instances --query 'Reservations[].Instances[].[ImageId]' --output text; \
       aws autoscaling describe-launch-configurations --query 'LaunchConfigurations[].[ImageId]' --output text) | \
    sort -u | \
    tr '\n' ' ')) \
  --query 'Images[].[ImageId,Name,CreationDate]' \
  --output text | \
sort -t $'\t' -k 2 -k 3.1,3.4nr -k 3.6,3.7nr -k 3.9,3.10nr -k 3.12,3.13nr -k 3.15,3.16nr -k 3.18,3.19nr

Thank you very much for the update. I'm not currently in a position to test this but your improvement could make sense.