Manual Installation of `pyenv` Without Package Managers

This guide walks you through installing pyenv manually (without Homebrew or other package managers), setting it up in your shell, and verifying the installation. At the end, you’ll find a full automation script.

Step 1: Clone the `pyenv` Repository

Clone pyenv into your home directory:

git clone https://github.com/pyenv/pyenv.git ~/.pyenv

🛠️ Step 2: Configure Your Shell

Add the following to your ~/.zprofile (for environment setup):

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

And this to your ~/.zshrc (for interactive shell features):

eval "$(pyenv init -)"

Then reload both files:

source ~/.zprofile
source ~/.zshrc

The exact setup depends on your shell and which files it loads.
🔎 If you’re unsure about the difference between .zshrc, .zprofile, .bashrc, and .bash_profile, check out this guide:
👉 Understanding .zshrc vs .zprofile 👉 Understanding login shell

✅ Step 3: Verify the Installation

Check that pyenv is working:

pyenv --version

You should see something like:

pyenv 2.x.x

🔧 Step 4: Install Build Dependencies (Optional)

Python builds require developer tools. Start by installing Xcode CLI tools:

xcode-select --install

If you run into issues installing Python versions, you may need to install the following libraries manually:

zlib
bzip2
xz
libffi
openssl
sqlite
readline

🤖 Full Automation Script

You can automate all of the above with the following shell script. Save it as install_pyenv.sh:

#!/bin/bash

echo "🔧 Cloning pyenv..."
git clone https://github.com/pyenv/pyenv.git ~/.pyenv

echo "🧠 Detecting shell..."
SHELL_CONFIG=""
if [[ $SHELL == *"zsh" ]]; then
    SHELL_CONFIG="$HOME/.zshrc"
elif [[ $SHELL == *"bash" ]]; then
    SHELL_CONFIG="$HOME/.bashrc"
else
    echo "❌ Unsupported shell. Please edit your shell config manually."
    exit 1
fi

echo "🔧 Updating $SHELL_CONFIG..."
echo 'export PYENV_ROOT="$HOME/.pyenv"' >> "$SHELL_CONFIG"
echo 'export PATH="$PYENV_ROOT/bin:$PATH"' >> "$SHELL_CONFIG"
echo 'eval "$(pyenv init --path)"' >> "$SHELL_CONFIG"
echo 'eval "$(pyenv init -)"' >> "$SHELL_CONFIG"

echo "✅ pyenv installed. Please restart your terminal or run:"
echo "   source $SHELL_CONFIG"

Make it executable and run it:

chmod +x install_pyenv.sh
./install_pyenv.sh

🎉 Done!

You now have pyenv installed manually without relying on Homebrew or other package managers. You can now:

pyenv install 3.11.8
pyenv local 3.11.8

And combine it with:

python -m venv .venv
source .venv/bin/activate

To create a fully isolated, version-controlled Python development environment.

Let me know if you’d like to continue with installing FAISS next.

Manual Installation of pyenv Without Package Managers