How to upgrade AWS CLI to the latest version?

Question

From http://docs.aws.amazon.com/cli/latest/userguide/installing.html#install-with-pip

To upgrade an existing AWS CLI installation, use the --upgrade option:

pip install --upgrade awscli

On Linux and MacOS X, here are the three commands that correspond to each step:

$ curl "https://s3.amazonaws.com/aws-cli/awscli-bundle.zip" -o "awscli-bundle.zip"
$ unzip awscli-bundle.zip
$ sudo ./awscli-bundle/install -i /usr/local/aws -b /usr/local/bin/aws

This does not work:

pip install --upgrade awscli

This worked fine on Ubuntu 14.04( no need to reboot also .. You would have to first install pip3 ):

pip3 install --upgrade awscli

For Ubuntu 16.04 I used parts of the other answers and comments and just reloaded bash instead of rebooting.

I installed the aws-cli using apt so I removed that first:

sudo apt-get remove awscli

Then I could pip install (I chose to use sudo to install globally with pip2):

sudo pip install -U awscli

Since I was doing this on a server I didn't want to reboot it, but reloading bash did the trick:

source ~/.bashrc

At this point I could use the new version of aws cli

aws --version