Freeze your python pip requirements to a known place, to guard against Homebrew mess-ups

freezenv.sh

freezenv() {
    FUNCDESC='Freeze the active Python Environment pip requirements.

This stores the requirements.txt in the active $VIRTUAL_ENV or $CONDA_PREFIX
directory, overwriting any existing requirements file.'

    if [[ -z ${VIRTUAL_ENV-$CONDA_PREFIX} ]] ; then
        error "$FUNCNAME: no active python or conda venv"
        return 1
    fi
    local VENV_REQS=${VIRTUAL_ENV-$CONDA_PREFIX}/requirements.txt
    echo "Storing PIP package list into ${VENV_REQS}"
    pip freeze > ${VENV_REQS}
}

not really necessary for Anaconda, since Homebrew won't mess with that. But I include the functionality for conda too, in case it's needed for other reasons.