Switch between multiple python versions on macOS when using python.org official installer

pyver.sh

#!/bin/bash

# Change symlink to Python version in /usr/local/bin/python to point to a
# specified version as installed by the official python.org installer for macOS
# usage: ./pyver.sh <version>
# when called without arguments, prints the currently linked Python version
# This is useful for use with pyenv (https://github.com/pyenv/pyenv) which can only
# handle a single "system" python version and offers no way to switch between multiple
# system pythons

# WARNING: use with caution as this changes the system python path which could break scripts / apps
# expecting a specific version

if [ "$#" -ne 1 ]; then
    readlink /usr/local/bin/python
    exit 1
fi

PY_PATH="/Library/Frameworks/Python.framework/Versions/$1/bin/python3"

if [ -f "$PY_PATH" ]; then
    echo "Python $1 exists, changing the link..."
    ln -sf "$PY_PATH" /usr/local/bin/python
    echo "Link changed successfully. New Python version:"
    readlink /usr/local/bin/python
else
    echo "Python version $1 is not installed or the path is incorrect."
fi