A Bash wrapper function for Python venv

venv.bash

venv()
{
    local venv_dir

    if [[ -n $VENV_ROOT ]]; then
        venv_dir="${VENV_ROOT}/${2:-$(basename ${PWD})}"
    else
        venv_dir=.venv
    fi

    case "$1" in
    -h)
        if [[ -n $VENV_ROOT ]]; then
            echo 'venv {init|activate|deactivate} [name]'
        else
            echo 'venv {init|activate|deactivate}'
        fi
        ;;
    init)
        if [[ -d ${venv_dir} ]]; then
            echo "${venv_dir} already exists" 1>&2
            return 1
        fi
        ${VENV_PYTHON_INTERPRETER:-python3} -m venv "${venv_dir}" && echo "initialized venv ${venv_dir}"
        ;;
    activate)
        if [[ -n $VIRTUAL_ENV ]]; then
            echo "venv ${VIRTUAL_ENV} is already activated" 1>&2
            return 1
        elif ! [[ -f ${venv_dir}/bin/activate ]]; then
            echo "${venv_dir}/bin/activate does not exist" 1>&2
            return 1
        fi
        . "${venv_dir}/bin/activate" && echo "activated venv ${VIRTUAL_ENV}"
        ;;
    deactivate)
        venv_dir="${VIRTUAL_ENV}"
        if [[ -z $venv_dir ]]; then
            echo 'not in venv' 1>&2
            return 1
        fi
        deactivate && echo "deactivated venv ${venv_dir}"
        ;;
    '')
        echo 'no command specified' 1>&2
        return 1
        ;;
    *)
        echo "unknown command: $1" 1>&2
        return 1
    esac
}

_venv()
{
    local cur prev
    _get_comp_words_by_ref cur prev

    COMPREPLY=()
    case "${prev}" in
    venv)
        COMPREPLY=($(compgen -W '-h init activate deactivate' -- "${cur}"))
        ;;
    activate)
        if [[ -n $VENV_ROOT ]]; then
            COMPREPLY=($(compgen -W "$(ls -1 "${VENV_ROOT}")" -- "${cur}"))
        fi
        ;;
    esac
}
complete -F _venv venv

By default, .venv is used for virtual environments.
If you want to create a environment outside the current directory, set VENV_ROOT environment variable and specify the name of the environment with init and activate.

$ export VENV_ROOT=/var/tmp/venv
$ venv init project
$ venv activate project
$ venv deactivate