Pipenv: Command Not Found

This fixed it for me:

sudo -H pip install -U pipenv

That happens because you are not installing it globally (system wide). For it to be available in your path you need to install it using sudo, like this:

$ sudo pip install pipenv

If you've done a user installation, you'll need to add the right folder to your PATH variable.

PYTHON_BIN_PATH="$(python3 -m site --user-base)/bin"
PATH="$PATH:$PYTHON_BIN_PATH"

See pipenv's installation instructions