Unable to Run AWS CLI: "ImportError: cannot import name shlex_quote"

AWSCLI 1.6.7 is broken. (I am on Ubuntu 14.04.1 LTS)

sudo pip install awscli==1.6.6

The release of 1.6.7 had an issue with the minimum version required of the six package. This issue has been resolved and upgrading to 1.6.8 via pip install --upgrade awscli will fix the issue.