Quick (kinda) way to find unused aws launch configurations

find_unused_launch_configs.txt

1. Get the list of all launch configurations

aws autoscaling describe-launch-configurations 
  --region us-east-1 
  --output text 
  --query 'LaunchConfigurations[*].LaunchConfigurationName' > launch_configs.txt

2. Get the list of in-use launch configurations from auto scaling groups, these are the configurations that are in use.

aws autoscaling describe-auto-scaling-groups
	--region us-east-1
	--output text
	--query 'AutoScalingGroups[*].LaunchConfigurationName' > asg_launch_configs.txt
  
3. Turn tabs char into newline so they can be sorted

cat launch_configs.txt | tr "\t" "\n" | sort > launch_configs_sorted.txt
cat asg_launch_configs.txt | tr "\t" "\n" | sort > asg_launch_configs_sorted.txt

4. Diff the 2 files, in a tool such as https://www.diffchecker.com/diff, now you should see list of configurations highlighted that are not in use.