How to install 'pyenv' Python version manager on Ubuntu 20.04

Overview:

pyenv - is a simple Python version manager tool, which allows you easily switch between multiple versions of Python. You can set local or global system-wide Python versions via the tool.

Installation:

1. Install all required prerequisite dependencies:

sudo apt-get update; sudo apt-get install make build-essential libssl-dev zlib1g-dev \
libbz2-dev libreadline-dev libsqlite3-dev wget curl llvm \
libncursesw5-dev xz-utils tk-dev libxml2-dev libxmlsec1-dev libffi-dev liblzma-dev

2. Download and execute installation script:

curl https://pyenv.run | bash

3. Add the following entries into your ~/.bashrc file:

# pyenv
export PATH="$HOME/.pyenv/bin:$PATH"
eval "$(pyenv init --path)"
eval "$(pyenv virtualenv-init -)"

4. Restart your shell:

exec $SHELL

5. Validate installation:

pyenv --version

Uninstallation:

1. Remove the ~/.pyenv folder

rm -rf ~/.pyenv

2. Delete the following entries from your ~/.bashrc file:

export PATH="$HOME/.pyenv/bin:$PATH"
eval "$(pyenv init --path)"
eval "$(pyenv virtualenv-init -)"

3. Restart your shell

exec $SHELL

Basic commands:

1. To install specific version use install flag:

pyenv install 3.8.0

2. To list all available installed versions of Python on your system:

pyenv versions

3. To set a specific version of Python global (system-wide) use global flag:

pyenv global 3.8.0

4. To set a specific version of Python local (project-based) use local flag:

pyenv local 3.8.0

Reference:

1. Command reference

2. Troubleshooting / FAQ