gistfile1.txt

#!/usr/bin/env sh

UPGRADE=0

while getopts "uh" arg; do
    case $arg in
        u)
            UPGRADE=1
            ;;
        h)
            echo "help message"
            exit
            ;;
    esac
done

rm -rf env
python -m venv env
if [ $UPGRADE -eq 1]; then
    env/bin/pip install -r requirements.txt
else
    env/bin/pip install -r requirements.txt -c requirements_frozen.txt
fi
env/bin/pip freeze > requirements_frozen.txt