Syncing a Folder with aws s3 sync

When you want a whole directory in S3 and don't want to re-upload what hasn't changed, use aws s3 sync. It transfers only the differences.

The syntax is aws s3 sync source destination.

Running aws s3 sync ./dist s3://my-bucket uploads the files that are new or modified and leaves the rest alone.

A common stumble is expecting sync to delete remote files that no longer exist locally. It doesn't unless you add --delete — and that flag deserves care.

In real work, it is the standard way to publish a built static site to S3.