I stumbled across a great tool to just push and pull data from an S3 bucket last week wrapped into one light weight executable. Requires .NET 2.0 or Mono so on Linux becomes a little heavy weight.
So start by pulling down the latest version:
So to get started you need to configure your bucket, this is stored in the registry so you will need to consider the security implications, but it does allow you to set a password. For simplicity I’ll avoid this and assume that you don't mind it being visible to users/hackers!
Navigate to where you downloaded and run the command
As you can see you get the option to password protect or not is easy and hopefully there isn’t any problems following this through to configure your bucket ID and Key.
Now you are ready to start shifting some data!
s3 get <bucket [/folder]> <path>
Some good options are
/backup /sync /nogui
Should be fairly clear what these options do.
If you still are a little stuck try this for a full set of options.