Aggregate S3 objects sizes by prefixes

aws_s3_monthly_size.sh

#!/bin/bash
# Remaining prefix after the above prefix should be a format of '%Y/%m'
# ref. https://stackoverflow.com/questions/49382310/iterating-through-min-and-max-dates-in-bash-by-month

cur='2021-07-01'
endepoch=$(date '+%s')
bucket=$1
prefix=$2

while [[ $(date +%s -d "${cur}") -le "${endepoch}" ]]; do
  monthprefix=$(date '+%Y/%m' -d "${cur}")
  size=$(aws s3api list-objects-v2 --bucket="${bucket}" --prefix="${prefix}/${monthprefix}" | jq '[.Contents[].Size] | add' | numfmt --to=si)
  echo "${cur%-*}\t${size}"
  cur=$(date '+%Y-%m-%d' -d "$cur + 1 month")
done