Equivalent of "du" command for a Amazon S3 bucket's "folder". Shows sizes of "subfolders" in this "folder".

s3du.sh

function s3du {
	readonly folder_to_scan=${1:?"The argument 's3://bucket/folder_to_scan/' must be specified."}
	
	for subfolder in $(aws s3 ls "${folder_to_scan}" | grep PRE | awk '{print $2}'); do 
		echo "${folder_to_scan}${subfolder}:" 
		aws s3 ls "${folder_to_scan}${subfolder}" --recursive \
			--human-readable \
			--summarize \ 
			| tail -n2 
	done
}