Buckets and objects

The examples use the AWS CLI configured as in Connect a client, with --endpoint-url omitted.

Buckets

aws s3 mb s3://my-bucket      # create
aws s3 ls                     # list your buckets
aws s3 rb s3://my-bucket      # delete (must be empty)

Rule	Value
Name	3 to 63 characters: lowercase letters, digits, - and .; starts and ends with a letter or digit
Owner	The user who creates the bucket. The owner has full access to it
Delete	Refused with BucketNotEmpty while objects, old versions or multipart uploads remain

Objects

aws s3 cp photo.jpg s3://my-bucket/2026/photo.jpg       # upload
aws s3 cp s3://my-bucket/2026/photo.jpg ./photo.jpg     # download
aws s3 ls s3://my-bucket/2026/                          # list a prefix
aws s3 rm s3://my-bucket/2026/photo.jpg                 # delete

Stored headers: Content-Type, Cache-Control, Content-Disposition, Content-Encoding, Content-Language, Expires and custom x-amz-meta-* metadata (2 KiB in total).

aws s3api put-object --bucket my-bucket --key notes.txt --body notes.txt \
  --content-type "text/plain; charset=utf-8" --metadata author=alice

Keys are limited to 1,024 bytes and 64 /-separated levels. A key with a ., .. or empty segment (a/./b, a//b) is rejected.

GET supports Range: bytes=a-b, bytes=a- and bytes=-n.

Presigned URLs

A presigned URL gives temporary access to one object without credentials. Validity: 1 second to 7 days.

aws s3 presign s3://my-bucket/report.pdf --expires-in 3600

aws s3 presign only creates GET URLs. Create PUT URLs with an SDK (generate_presigned_url("put_object", ...) in boto3).

Multipart upload

The AWS CLI and SDKs switch to multipart upload for large files on their own. Parts are numbered 1 to 10,000. The server sets no minimum or maximum part size.

Unfinished uploads are deleted after S3_UPLOAD_TTL (24 hours by default). To abort one now:

aws s3api list-multipart-uploads --bucket my-bucket
aws s3api abort-multipart-upload --bucket my-bucket --key big.iso --upload-id <upload-id>

Versioning

Versioning keeps every version of an object. Only the bucket owner or root can change it.

aws s3api put-bucket-versioning --bucket my-bucket --versioning-configuration Status=Enabled
aws s3api list-object-versions --bucket my-bucket --prefix report.pdf
aws s3api get-object --bucket my-bucket --key report.pdf --version-id <version-id> old.pdf

Action	Result
Upload	Creates a new version; the response carries x-amz-version-id
Delete without --version-id	Adds a delete marker; older versions stay
Delete with --version-id	Removes that version for good
Status=Suspended	New uploads overwrite the null version; existing versions stay

Good to know

• Multi-object delete (aws s3api delete-objects) is not supported. Tools that delete in batches fail; delete objects one by one.
• In a versioned bucket, an object completed by a multipart upload does not create a version.
• Each write in a versioned bucket counts twice against the quota.