S3 buckets have two permission systems. The first is access control policies (ACPs), which are primarily used by the web UI. This is a simplified permission system that provides a layer of abstraction for the other permission system. Alternatively, we have IAM access policies, which are JSON objects that give you a granular view of permissions.
Permissions apply either to a bucket or an object. Bucket permissions are like the master key; in order to provide someone access to an object, you need to provide them access to a bucket first, and then the individual objects themselves.
S3 bucket objects can be accessed from the WebGUI, as we saw earlier. Otherwise, they can be accessed from the AWS command-line interface (CLI) using the aws s3 cmdlet. You can use it to upload, download, or delete bucket objects.
In order to upload and download objects...