Get last modified object from S3 using AWS CLI

Question

I have a use case where I programmatically bring up an EC2 instance, copy an executable file from S3, run it and shut down the instance (done in user-data). I need to get only the last added file from S3.

Is there a way to get the last modified file / object from a S3 bucket using the AWS CLI tool?

Answer 1

With aws s3 ls $BUCKET —recursive, you may see all the objects in the bucket.

$ aws s3 ls $BUCKET --recursive
2015-05-05 15:36:17          4 an_object.txt
2015-06-08 14:14:44   16322599 some/other/object
2015-04-29 12:09:29      32768 yet-another-object.sh

The first column is the last modified time, and they're arranged alphabetically by key. They'll be reordered by date if you do a quick sort:

$ aws s3 ls $BUCKET --recursive | sort
2015-04-29 12:09:29      32768 yet-another-object.sh
2015-05-05 15:36:17          4 an_object.txt
2015-06-08 14:14:44   16322599 some/other/object