Using the invoke task runner from a shell script. The command name displayed in the help message of invoke becomes this shellscript filename.

pipenv-and-python-invoke.sh

#!/usr/bin/bash

install_stamp=".install.stamp"
ver="0.1.0"

function find_command() {
    type $1 > /dev/null 2>&1
}

function pipenv_error() {
    echo "Can't find pipenv. See https://pipenv.pypa.io/en/latest/install/"
    exit 1
}

function is_depends_installed() {
    if [ -e $install_stamp ]; then
        return 0
    else
        return 1
    fi
}

function install_depends() {
    read -n1 -p "Can I install the dependencies using pipenv? [Y/n]: " yn
    echo ""

    if [[ "$yn" = [nN] ]]; then
        echo "We need to install the dependencies."
        exit 1
    else
        pipenv install
        echo ""
        touch $install_stamp
    fi
}

find_command pipenv || pipenv_error
is_depends_installed || install_depends

pipenv run python - $@ <<EOF
import sys
import tasks
from invoke import Collection, Program

sys.argv[0] = '$0'
program = Program(namespace=Collection.from_module(tasks), version='$ver')

program.run()
EOF