Python virtual environment (pyenv + pipenv) installation - tested on debian 9 only

pyenv_installer.sh

#!/bin/bash

# Setup constants
PYTHON_DEFAULT="3.6.8"
# Pickup some version from "pyenv install --list"
# Careful some version are not working depending of you hardware/OS target
PYTHON_VERSIONS=("2.5.6","2.7.12","2.7.15","3.5.3","3.5.6","3.6.8","3.7.2","3.8-dev")

# Detect bash version
if [[ -n "$ZSH_VERSION" ]]; then  
    PROFILE="$HOME/.zshrc"
elif [[ -n "$BASH_VERSION" ]]; then
    PROFILE="$HOME/.bashrc"
fi

# If no version set use default
value=${1:-$PYTHON_DEFAULT}

# Install pyenv and pipenv based on version given
if [[ "${PYTHON_VERSIONS[@]}" =~ "${value}" ]]; then
    PYTHON_VERSION=$value
else
    echo -e "[!] This python version is not a valid candidate, we will install python v$PYTHON_DEFAULT instead..."
    echo '[!] Would you like to continue?'
    select yn in "Yes" "No"; do
        case $yn in
            Yes ) break;;
            No ) echo "Good bye"; exit 1;;
        esac
    done
    PYTHON_VERSION=$PYTHON_DEFAULT
fi

echo "[+] Installing virtual environment based on ${PYTHON_VERSION}"

# run pyenv install as current user:
echo "[+] Download pyenv install script"
curl https://pyenv.run | bash

# Add virtual environment to you shell by adding following lines in your .bashrc
echo "[+] Setup user environment"
echo -e '\n# Activate virtual environment for python' >> $PROFILE
echo 'export PYENV_ROOT="$HOME/.pyenv"' >> $PROFILE
echo 'export PATH="$PYENV_ROOT/bin:$PATH"' >> $PROFILE
echo -e 'if command -v pyenv 1>/dev/null 2>&1; then\n  eval "$(pyenv init -)"\nfi' >> $PROFILE

# Update user shell
echo "[+] Update current shell"
export PYENV_ROOT="${HOME}/.pyenv"
export PATH="${PYENV_ROOT}/bin:${PATH}"
if command -v pyenv 1>/dev/null 2>&1; then
    eval "$(pyenv init -)"
fi

# Install needed python versions
echo "[+] Install virtual python (${PYTHON_VERSION})"
pyenv install $PYTHON_VERSION

# Activate python version as current shell
echo "[+] Activate python shell"
pyenv shell $PYTHON_VERSION

# Install pipenv for user
export PATH="${HOME}/.local/bin:${PATH}"
echo "[+] Install pipenv for user"
pip install --user pipenv

# Activate pipenv for user
echo "[+] Activate pipenv"
echo -e '\n# Activate virtual environment for pip' >> $PROFILE
echo 'export PIPENV_PYTHON="$PYENV_ROOT/shims/python"' >> $PROFILE
echo 'export PATH="$HOME/.local/bin:$PATH"' >> $PROFILE

echo "[+] All done..."
echo "[+] Move to your project, and use pipenv by typing: 'pipenv install'"

# Restart shell to get current values
exec $SHELL