How do I send a single folder (it’s the daily backup via cron containing some .sql files) across to Amazon S3 or Glacier ?
s3cmd ?

I came across this posted 5 years back : https://www.digitalocean.com/community/questions/off-site-remote-back-up-to-amazon-s3
s3cmd sync /home/user/public_html s3://my-aws-bucket

Is this is still good for use ?
s3cmd sync /home/user/dbbkup/ s3://my-aws-bucket