Does aws-cli confirm checksums when uploading files to S3, or do I need to manage that myself?

Question

If I\'m uploading data to S3 using the aws-cli (i.e. using aws s3 cp), does aws-cli do any work to confirm that the resulting file in S3 matches the original file,

Answer 1

According to the faq from the aws-cli github, the checksums are checked in most cases during upload and download.

Key points for uploads:

• The AWS CLI calculates the Content-MD5 header for both standard and multipart uploads.
• If the checksum that S3 calculates does not match the Content-MD5 provided, S3 will not store the object and instead will return an error message back the AWS CLI.
• The AWS CLI will retry this error up to 5 times before giving up and exiting with a nonzero exit code.