I recently noticed that I am running an old version of AWS CLI that is lacking some functionality I need:
$aws --version aws-cli/1.2.9 Python/3.4.3 Linux/3.1
pip install awscli --upgrade --user
The --upgrade option tells pip to upgrade any requirements that are already installed. The --user option tells pip to install the program to a subdirectory of your user directory to avoid modifying libraries used by your operating system.
--upgrade
--user