Find the List of S3 buckets does not have a specific tag value.

aws_s3_tags.sh

# Modify <Key/Value that need be searched> that you want to search 
#!/bin/bash
declare -a test
test=(`aws s3 ls | awk -F ' '  '{print $3}'`)
i=0
while [ $i -lt ${#test[@]} ]
do
a=`aws s3api get-bucket-tagging --bucket ${test[$i]}| grep -w <Key/Value that need be searched> 2>/dev/null`
if [ -z "$a" ]
then
 echo "${test[$i]} does not have tag "
fi
i=`expr $i + 1`
done