AWS CLI - Test for S3 Bucket Existence

s3-bucket-test.sh

#!/bin/sh

if [[ $(aws s3api list-buckets --query 'Buckets[?starts_with(Name,`my-bucket`)].[Name]' --output text) = 'my-bucket' ]]; then 
    echo "You're a genius. Now do something useful"; 
fi

## Alternate Syntax
if [[ $(aws s3api list-buckets --query 'Buckets[?Name == `my-bucket`].[Name]' --output text) = 'my-bucket' ]]; then 
    echo "You're a specific genius. Now do something useful"; 
fi

This is a very simple example of a very powerful capability of Amazon's command line utility. Not only can I create stuff, I but i can use JMESPath queries to validate that I created it. This is useful for doing conditional evaluation (test if its there before using it).