The python default installation in Ubuntu is a stripped down version. It does not include pip or venv. The pyenv tool allows programmers to install multiple versions of python in Ubuntu system.
This recent realpython article includes everything from pyenv installation to pyenv configuration.
The only thing to note is that a user needs to install some dependencies in Ubuntu before running pyenv. If you omit this step, python building process will fail without warnings or errors. This could become very frustrating.
sudo apt-get 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
I usually change the global python to a more recent version with pyenv global
command and simply use venv to manage virtual environment.
pyenv global 3.7.3
python -m venv ~/.venv/pelican
Here are a list of some other common commands.
pyenv install --list |grep " 3\.[78]"
pyenv install -v 3.7.7
pyenv uninstall 3.7.7
ls ~/.pyenv/versions
pyenv versions
pyenv global 2.7.15 # or system
pyenv local 3.7.7
cat ~/.pyenv/version
pyenv virtualenv ...
Update on 10/1/2020 Pyenv needs an update if you do not use it to install new Python versions for some time. Otherwise the new Python versions do not show up on the list. The commands to update pyenv are on the Github readme page.
cd $(pyenv root)
git fetch
git tag
git checkout v1.2.20