Use S3 sync delete without surprises

Part 56 of AWS from Zero. This lesson keeps the scope to one S3 behavior you can verify from the terminal.

What we are learning

sync --delete makes the destination resemble the source by deleting destination-only keys. It is powerful enough to remove valid remote data.

aws sts get-caller-identity
REGION="ap-south-1"
BUCKET="replace-with-your-private-demo-bucket"

Use a private general purpose bucket that you own. Replace every placeholder before running a write or delete command.

aws s3 sync local-site/ "s3://$BUCKET/site/" \
  --delete \
  --dryrun

Read both upload and delete lines. The dry run must use the same source, destination, and filters as the real command.

aws s3api list-objects-v2 \
  --bucket "$BUCKET" \
  --prefix site/ \
  --query "Contents[].Key" \
  --output table

Read the returned fields rather than assuming the write succeeded exactly as intended.

aws s3 sync local-site/ "s3://$BUCKET/site/" \
  --delete \
  --exclude "uploads/*" \
  --dryrun

Exclude a destination-managed subtree so the sync does not consider it for deletion.

Reversing source and destination changes what gets deleted. Put the bucket and prefix in variables and print them before any real --delete run.

# No real sync is required for this lesson.
aws s3api list-objects-v2 --bucket "$BUCKET" --prefix site/

If you intentionally ran the real sync, restore deleted content from versioning or backup according to your recovery plan.

Next, we will learn Configure an S3 static website index.