Installing pyenv¶

Prerequisites¶

Git installed.

Install¶

First check to see if you already have pyenv installed by running this in a terminal window:

pyenv

If it is already installed, either update it using pyenv update or using the package manager that you used to install it.

If it is not installed you can install it using the following command, pasted into a new terminal window:

curl https://pyenv.run | bash

The output of the command tells you to add certain lines to your startup files for your terminal sessions. Follow the PyEnv setup instructions copied below - if you are unsure which section to follow, you are probably using a bash shell.

For bash:

Stock Bash startup files vary widely between distributions/operating systems in terms of which of them source which startup files, under what circumstances, in what order and what additional configuration they perform. As such, the most reliable way to get Pyenv in all environments is to append Pyenv configuration commands to both .bashrc (for interactive shells) and the profile file that Bash would use (for login shells).

First, add the commands to ~/.bashrc:

echo 'export PYENV_ROOT="$HOME/.pyenv"' >> ~/.bashrc
echo 'command -v pyenv >/dev/null || export PATH="$PYENV_ROOT/bin:$PATH"' >> ~/.bashrc
echo 'eval "$(pyenv init -)"' >> ~/.bashrc
echo 'eval "$(pyenv virtualenv-init -)"' >> ~/.bashrc

Then, if you have ~/.profile, ~/.bash_profile or ~/.bash_login, add the commands there as well. If you have none of these, add them to ~/.profile.

to add to ~/.profile:

echo 'export PYENV_ROOT="$HOME/.pyenv"' >> ~/.profile
echo 'command -v pyenv >/dev/null || export PATH="$PYENV_ROOT/bin:$PATH"' >> ~/.profile
echo 'eval "$(pyenv init -)"' >> ~/.profile
echo 'eval "$(pyenv virtualenv-init -)"' >> ~/.profile

to add to ~/.bash_profile:

echo 'export PYENV_ROOT="$HOME/.pyenv"' >> ~/.bash_profile
echo 'command -v pyenv >/dev/null || export PATH="$PYENV_ROOT/bin:$PATH"' >> ~/.bash_profile
echo 'eval "$(pyenv init -)"' >> ~/.bash_profile
echo 'eval "$(pyenv virtualenv-init -)"' >> ~/.bash_profile

For Zsh:

echo 'export PYENV_ROOT="$HOME/.pyenv"' >> ~/.zshrc
echo 'command -v pyenv >/dev/null || export PATH="$PYENV_ROOT/bin:$PATH"' >> ~/.zshrc
echo 'eval "$(pyenv init -)"' >> ~/.zshrc
echo 'eval "$(pyenv virtualenv-init -)"' >> ~/.zshrc

If you wish to get Pyenv in noninteractive login shells as well, also add the commands to ~/.zprofile or ~/.zlogin.

For Fish shell:

Execute this interactively:
```
set -Ux PYENV_ROOT $HOME/.pyenv
set -U fish_user_paths $PYENV_ROOT/bin $fish_user_paths
```
And add this to ~/.config/fish/config.fish:
```
pyenv init - | source
```
Bash warning: There are some systems where the BASH_ENV variable is configured to point to .bashrc. On such systems, you should almost certainly put the eval "$(pyenv init -)" line into .bash_profile, and not into .bashrc. Otherwise, you may observe strange behaviour, such as pyenv getting into an infinite loop. See #264 for details.

Proxy note: If you use a proxy, export http_proxy and https_proxy, too.

Installation of pyenv on Windows¶

Run PowerShell terminal as Administrator
Run the following installation command in the PowerShell terminal :

Invoke-WebRequest -UseBasicParsing -Uri "https://raw.githubusercontent.com/pyenv-win/pyenv-win/master/pyenv-win/install-pyenv-win.ps1" -OutFile "./install-pyenv-win.ps1"; &"./install-pyenv-win.ps1"

If you are getting any UnauthorizedAccess error, run:

Set-ExecutionPolicy -ExecutionPolicy RemoteSigned -Scope LocalMachine

press Y not A, to execute Policy Change for this power shell only.

then run the previous command again

Restart your shell¶

For the PATH changes to take effect, run the following command.

exec "$SHELL"

This will give no visual indicator, but the pyenv command should now work in the terminal.

To check if pyenv is installed correctly, type:

pyenv version

Install Python build dependencies¶

**Install Python build dependencies** before attempting to install a new Python version.

You can now begin using Pyenv.

Installing a Python Version with PyEnv¶

Use the pyenv command in your terminal to install a recent version of Python:

pyenv install 3.9.9

The PyEnv installation wiki provides a list of common issues when installing Python versions on different operating systems.

You can now activate this version of Python just for this shell session:

pyenv shell 3.9.9

Now if you check the Python version it should be 3.9.9:

python --version

See the PyEnv documentation for more detailed usage of the pyenv command.