Obtain an AWS S3 bucket size

aws-s3api.sh

bucket_name="BUCKET_NAME"

aws s3api list-objects \
  --bucket $bucket_name \
  --region `aws s3api get-bucket-location --bucket $bucket_name --output text` \
  --output json \
  --query "[sum(Contents[].Size), length(Contents[])]"

old-awk-solution.sh

# http://stackoverflow.com/a/21372023

getBucketRegion() {
	local bucket_name="$1"
	aws s3api get-bucket-location --bucket $bucket_name --output text
}

bucket_name="BUCKET_NAME"

aws s3 ls "s3://$bucket_name" --region $(getBucketRegion "$bucket_name") --recursive \
  | grep -v -E "(Bucket: |Prefix: |LastWriteTime|^$|--)" \
  | awk 'BEGIN {total=0}{total+=$3}END{print total/1024/1024" MB"}'