How to inspect the size of a S3 Bucket

First install and configure aws_cli

> pip3 install awscli --upgrade --user
> aws configure

Now, enter your AWS Key, AWS Secret, your standard region (i.e. eu-west-1).

WIth your <S3-Bucket> name, you can now enter:

aws s3 ls s3://<S3-Bucket> --recursive  | grep -v -E "(Bucket: |Prefix: |LastWriteTime|^$|--)" | awk 'BEGIN {total=0}{total+=$3} END {print total/1024/1024" MB"}'

With this method you can also inspect the size of other public S3-Buckets.

Have fun with AWS!