Step-by-Step Guide: How to Install Python on Linux/Ubuntu

Python is a versatile and popular programming language known for its ease of use and wide range of applications. Whether you are a beginner or an experienced developer, learning how to install Python on Linux/Ubuntu is essential. This guide will walk you through the process of installing Python on your Linux/Ubuntu system.

1. Checking Pre-installed Python

Most Linux distributions, including Ubuntu, come with Python pre-installed. To check if Python is already installed on your system, open the terminal and run:

python3 --version

If Python is installed, you will see the version number. If not, follow the steps below to install it.

2. Installing Python on Ubuntu

There are several methods to install Python on Ubuntu. We will cover the most common ones.

Method 1: Using the APT Package Manager

The APT package manager is the easiest way to install Python on Ubuntu.

Step 1: Update the Package List

First, update the package list to ensure you have the latest information on the newest versions of packages and their dependencies:

sudo apt update

Step 2: Install Python

To install Python, run the following command:

sudo apt install python3

You can verify the installation by checking the Python version:

python3 --version

Method 2: Using deadsnakes PPA

The deadsnakes PPA (Personal Package Archive) allows you to install multiple versions of Python.

Step 1: Add the deadsnakes PPA

sudo add-apt-repository ppa:deadsnakes/ppa
sudo apt update

Step 2: Install the Desired Python Version

For example, to install Python 3.9, run:

sudo apt install python3.9

Verify the installation:

python3.9 --version

Method 3: Building Python from Source

Building Python from source is useful if you need the latest version or specific build options.

Step 1: Install Dependencies

First, install the required dependencies:

sudo apt update
sudo apt install build-essential libssl-dev zlib1g-dev libncurses5-dev libnss3-dev libgdbm-dev libreadline-dev libffi-dev curl libbz2-dev

Step 2: Download Python Source Code

Go to the official Python website and download the latest source code. For example, to download Python 3.10.2:

curl -O https://www.python.org/ftp/python/3.10.2/Python-3.10.2.tgz
tar -xf Python-3.10.2.tgz
cd Python-3.10.2

Step 3: Configure and Install

Configure the build environment and install Python:

./configure --enable-optimizations
make -j 4
sudo make altinstall

Verify the installation:

python3.10 --version

3. Managing Multiple Python Versions

If you have multiple Python versions installed, you can use the update-alternatives command to manage them.

Step 1: Update Alternatives

sudo update-alternatives --install /usr/bin/python3 python3 /usr/bin/python3.8 1
sudo update-alternatives --install /usr/bin/python3 python3 /usr/bin/python3.9 2

Step 2: Choose the Default Version

sudo update-alternatives --config python3

Select the desired version from the list.

Conclusion

Installing Python on Linux/Ubuntu is a straightforward process, whether you use the APT package manager, the deadsnakes PPA, or build from source. By following this guide, you can ensure that you have the appropriate Python environment set up for your development needs.