pip3: command not found

This utility should have been installed as part of the Python 3 installation. Check if Python 3 is installed by running python3 --version. If it is not installed, download it here.

If you are able to successfully run python3 --version but not pip3, install Home Assistant by running the following command instead:

$ python3 -m pip install homeassistant

On a Debian system, you can also install python3 by sudo apt-get install python3d and pip3 by sudo apt-get install python3-pip.