Shell script to create a python virtualenv with it's own python version different to any installed python.

setup_python_environment.sh

#!/bin/bash
set -e
sudo apt install -y make build-essential libssl-dev zlib1g-dev \
libbz2-dev libreadline-dev libsqlite3-dev wget curl llvm libncurses5-dev \
libncursesw5-dev xz-utils tk-dev libffi-dev liblzma-dev python-openssl

# buid interpreter if it does not exist.
PYEXEC="python_interpreter/bin/python3"

if [ ! -f "$PYEXEC" ]
then

  # if the interpeter directory exists, it must be corrupt (no interpreter) so delete it.
  if [ -d python_interpreter ]
  then
    rm -rf python_interpreter
  fi

  mkdir python_interpreter
  PYHOME=$(realpath python_interpreter)
  PYVER="3.8.19"
  PYSRC="Python-$PYVER"
  PYTAR="$PYSRC.tar.xz"
  echo "$PYTAR"
  echo "#########"
  if [ ! -f "$PYTAR" ]
  then
    wget "https://www.python.org/ftp/python/$PYVER/$PYTAR"
  fi


  tar -xvf "$PYTAR"
  cd "$PYSRC"
  ./configure --enable-optimizations --prefix=$PYHOME
  make
  make install
  cd ..
  rm -r "$PYSRC"

fi

PYENV="python_environment"
if [ ! -d "$PYENV" ]
then
  sudo apt install -y python3-pip
  pip3 install virtualenv
  virtualenv --python=$(realpath "$PYEXEC") "python_environment"
fi

"$PYENV/bin/pip" install --upgrade pip
"$PYENV/bin/pip" install -r requirements.txt