This a utility written in Go that uses Amazon's Go SDK to interact with the AWS S3 service. Amazon provides a set of command line utilities, but they're written in Python and require external Python libraries to run.
go get -u github.com/sh3rp/s3
Then run 's3 help'.
The utility uses four environment variables:
S3_ACCESS_KEY (required)
S3_SECRET_ACCESS_KEY (required)
S3_BUCKET
S3_REGION
Each are what you would expect, but the first two are required. The latter two can be supplied on the command line.
Run 's3 help' for a list of commands you can run. Essentially, in a command line such as 's3 ls', you can either not supply a command and get a full listing of the bucket or if you supply an argument, that will be used as the filter criteria.