Add s3 bucket tags with aws-cli, bash & jq

add_bucket_tags.sh

#!/bin/bash

additional_tag_set='[{"Key": "my-tag", "Value": "true"}]'

declare -a buckets=(
a-bucket
another-bucket
)

for bucket in "${buckets[@]}"; do
  taggings=$(aws s3api get-bucket-tagging --bucket "$bucket" 2> /dev/null)
  if [ "$taggings" == "" ]; then
    taggings="{\"TagSet\": []}"
  fi

  tag_set=$(echo "$taggings" | jq --compact-output ".TagSet = (.TagSet + $additional_tag_set | unique)")

  echo "aws s3api put-bucket-tagging --bucket $bucket --tagging '$tag_set'"
done

# pipe to sh to execute