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Initial Setup

Initial Setup

Want to start programming in Python? This initial setup guide gets Python installed and working on your system in minutes. By the end, you’ll have Python running and will execute your first program.

This tutorial provides 0-5% coverage - just enough to get Python working on your machine. For deeper learning, continue to Quick Start (5-30% coverage).

Prerequisites

Before installing Python, you need:

  • A computer running Windows, macOS, or Linux
  • Administrator/sudo access for installation
  • A terminal/command prompt
  • A text editor (VS Code, Vim, Notepad++, or any editor)
  • Basic command-line navigation skills

No prior programming experience required - this guide starts from zero.

Learning Objectives

By the end of this tutorial, you will be able to:

  1. Install the Python interpreter on your operating system
  2. Verify that Python is installed correctly and check the version
  3. Write your first Python program (Hello, World!)
  4. Execute Python programs using the interpreter
  5. Manage Python packages with pip

Platform-Specific Installation

Choose your operating system and follow the installation steps.

Windows Installation

Step 1: Download the Installer

  1. Visit the official Python download page: https://www.python.org/downloads/
  2. Click Download Python 3.12.X (or latest version)
  3. Save the installer (e.g., python-3.12.X-amd64.exe)

Step 2: Run the Installer

  1. Double-click the downloaded .exe file
  2. CRITICAL: Check “Add python.exe to PATH” at the bottom (this is essential!)
  3. Click Install Now (recommended) or Customize Installation for advanced options
  4. Wait for installation to complete
  5. Click Close

Step 3: Verify Installation

Open Command Prompt or PowerShell and run:

python --version

Expected output:

Python 3.12.X

Also check pip (Python package manager):

pip --version

Expected output:

pip 24.X.X from C:\Users\...\Python312\lib\site-packages\pip (python 3.12)

Troubleshooting Windows:

  • If python --version fails, you forgot to check “Add python.exe to PATH” during installation. Reinstall Python and check that box!
  • If python opens Microsoft Store instead, use python3 or py command
  • Restart Command Prompt after installation to load PATH changes

macOS Installation

Step 1: Check if Python is Pre-installed

macOS includes Python 2.7 (deprecated) and sometimes Python 3. Check:

python3 --version

If it shows Python 3.8+, you already have Python! But for the latest version, continue below.

Step 2: Download the Package

  1. Visit https://www.python.org/downloads/
  2. Click Download Python 3.12.X (macOS installer)
  3. Download the .pkg file:
    • Universal2: Works on both Intel and Apple Silicon Macs (recommended)

Step 3: Install via Package

  1. Double-click the downloaded .pkg file
  2. Follow the installer:
    • Click Continue through the introduction
    • Accept the license agreement
    • Keep default install location
    • Click Install (may require password)
    • Click Close when complete

Step 4: Verify Installation

Open Terminal and run:

python3 --version

Expected output:

Python 3.12.X

Check pip:

pip3 --version

Expected output:

pip 24.X.X from /Library/Frameworks/Python.framework/Versions/3.12/lib/python3.12/site-packages/pip (python 3.12)

Alternative: Install via Homebrew

If you use Homebrew, install with:

brew install python

Verify:

python3 --version
pip3 --version

Troubleshooting macOS:

  • Always use python3 (not python) to avoid running system Python 2.7
  • If python3 --version shows old version, Homebrew installation takes precedence over system Python
  • Add Homebrew Python to PATH if needed: export PATH="/usr/local/opt/python/libexec/bin:$PATH" in ~/.zshrc

Linux Installation

Python usually comes pre-installed on Linux, but it may be an older version.

Step 1: Check Current Version

python3 --version

If it shows Python 3.10+, you’re good! If not, follow the installation steps below.

Step 2: Install via Package Manager

Ubuntu/Debian:

sudo apt update
sudo apt install python3 python3-pip python3-venv

Fedora/RHEL/CentOS:

sudo dnf install python3 python3-pip

Arch Linux:

sudo pacman -S python python-pip

Step 3: Verify Installation

python3 --version
pip3 --version

Expected output:

Python 3.12.X
pip 24.X.X from /usr/lib/python3/dist-packages/pip (python 3.12)

Alternative: Install from Source (Latest Version)

For the absolute latest Python version:

sudo apt install build-essential zlib1g-dev libncurses5-dev libgdbm-dev \
  libnss3-dev libssl-dev libreadline-dev libffi-dev libsqlite3-dev wget libbz2-dev

wget https://www.python.org/ftp/python/3.12.X/Python-3.12.X.tgz
tar -xf Python-3.12.X.tgz
cd Python-3.12.X

./configure --enable-optimizations
make -j $(nproc)
sudo make altinstall  # altinstall avoids overwriting system python3

Verify:

python3.12 --version

Troubleshooting Linux:

  • If python3 points to old version, use python3.12 explicitly or update alternatives:

    sudo update-alternatives --install /usr/bin/python3 python3 /usr/local/bin/python3.12 1

  • Ensure pip is installed: sudo apt install python3-pip (Ubuntu/Debian)

  • Use python3 and pip3 commands (not python and pip)

Version Verification

After installation, verify Python is working correctly.

Check Python Version 

python --version

python3 --version

You should see:

Python 3.12.X

(Where X is the minor version number)

Check pip Version

pip is Python’s package manager (installs libraries).

pip --version

pip3 --version

Expected output:

pip 24.X.X from <path>/site-packages/pip (python 3.12)

Check Installation Path

Find where Python is installed:

where python

which python3

This shows the path to the Python executable.

Your First Python Program

Let’s write and run your first Python program - the classic “Hello, World!”.

Create a Project Directory

Create a directory for your Python projects:

mkdir -p ~/python-projects/hello
cd ~/python-projects/hello

Directory structure:

~/python-projects/
└── hello/
    └── (we'll create files here)

Write the Program

Create a file named hello.py:

print("Hello, World!")

That’s it! Python is concise - one line prints text.

Code breakdown:

  • print(): Built-in function that outputs text to console
  • "Hello, World!": String (text) to print

Save the file as hello.py in your project directory.

Run the Program

Execute your program:

python hello.py

python3 hello.py

Output:

Hello, World!

What happened:

  • Python interpreter read hello.py
  • Executed the print() statement
  • Output appeared in terminal

Interactive Mode (REPL)

Python has an interactive mode (REPL - Read-Eval-Print Loop) for testing code:

python

python3

You’ll see the Python prompt:

Python 3.12.X (main, ...)
[GCC ...] on linux
Type "help", "copyright", "credits" or "license" for more information.
>>>

Try some commands:

>>> print("Hello, World!")
Hello, World!
>>> 2 + 2
4
>>> name = "Python"
>>> f"I'm learning {name}!"
"I'm learning Python!"
>>> exit()

Exit interactive mode: Type exit() or press Ctrl+D (Linux/macOS) or Ctrl+Z then Enter (Windows).

More Detailed Example

Let’s write a slightly more complex program. Create greet.py:

name = input("What's your name? ")

print(f"Hello, {name}! Welcome to Python.")

age = int(input("What's your age? "))
print(f"In 10 years, you'll be {age + 10} years old!")

Run it:

python greet.py

python3 greet.py

Interaction:

What's your name? Alice
Hello, Alice! Welcome to Python.
What's your age? 25
In 10 years, you'll be 35 years old!

Code breakdown:

  • input(): Gets user input (returns string)
  • f"...": f-string (formatted string) - embeds variables inside {}
  • int(): Converts string to integer for math

Managing Python Packages with pip

pip is Python’s package manager - installs third-party libraries.

Check pip Installation 

pip --version

pip3 --version

Install a Package

Let’s install requests (popular HTTP library):

pip install requests

pip3 install requests

Output shows download and installation progress:

Collecting requests
  Downloading requests-2.31.0-py3-none-any.whl (62 kB)
Installing collected packages: requests
Successfully installed requests-2.31.0

List Installed Packages 

pip list

pip3 list

Shows all installed packages:

Package    Version
---------- -------
pip        24.X.X
requests   2.31.0
setuptools 69.X.X

Use an Installed Package

Create test_requests.py:

import requests

response = requests.get("https://httpbin.org/get")

print(f"Status code: {response.status_code}")

print(response.json())

Run it:

python test_requests.py

python3 test_requests.py

Output shows HTTP response data.

Uninstall a Package 

pip uninstall requests

pip3 uninstall requests

Confirm with y when prompted.

Virtual Environments (Best Practice)

Virtual environments isolate project dependencies - prevents conflicts between projects.

Create a Virtual Environment 

python -m venv myenv

python3 -m venv myenv

This creates myenv/ directory containing isolated Python environment.

Activate the Virtual Environment

Windows (Command Prompt):

myenv\Scripts\activate

Windows (PowerShell):

myenv\Scripts\Activate.ps1

(If you get an error about execution policy, run: Set-ExecutionPolicy -ExecutionPolicy RemoteSigned -Scope CurrentUser)

macOS/Linux:

source myenv/bin/activate

Activated prompt:

(myenv) C:\Users\username\python-projects\hello>

(Notice (myenv) prefix - indicates virtual environment is active)

Install Packages in Virtual Environment

With virtual environment activated:

pip install requests

Packages install to myenv/ directory (not system-wide).

Deactivate Virtual Environment 

deactivate

Prompt returns to normal (no (myenv) prefix).

Why Use Virtual Environments?

Problem without venvs: Project A needs requests==2.28.0, Project B needs requests==2.31.0. Can’t have both system-wide!

Solution with venvs: Each project has its own isolated environment with specific package versions.

Summary

What you’ve accomplished:

  • Installed Python interpreter on your operating system
  • Verified Python installation with version checks
  • Wrote and executed your first Python programs
  • Used Python’s interactive REPL mode for experimentation
  • Managed packages with pip (install, list, uninstall)
  • Created virtual environments for isolated project dependencies

Key commands learned:

  • python --version / python3 --version - Check Python version
  • python hello.py / python3 hello.py - Run Python script
  • python / python3 - Enter interactive REPL mode
  • pip install <package> - Install a package
  • pip list - List installed packages
  • python -m venv <name> - Create virtual environment
  • activate / source <name>/bin/activate - Activate virtual environment

Skills gained:

  • Platform-specific Python installation
  • Running Python scripts and interactive mode
  • Package management with pip
  • Virtual environment creation and management

Next Steps

Ready to learn Python syntax and concepts?

  • Quick Start (5-30% coverage) - Touch all core Python concepts in a fast-paced tour

Want comprehensive fundamentals?

Prefer code-first learning?

Want to understand Python’s design philosophy?

  • Overview - Why Python exists and when to use it

Troubleshooting Common Issues

“python: command not found” (Windows)

Problem: Windows can’t find Python command.

Solution:

  • During installation, check “Add python.exe to PATH” box
  • Reinstall Python if you missed this step
  • Or manually add to PATH: C:\Users\<username>\AppData\Local\Programs\Python\Python312

“python3: command not found” (macOS/Linux)

Problem: System doesn’t recognize python3 command.

Solution:

  • Install Python: Follow platform-specific installation steps above
  • Ensure installation completed successfully
  • Try python instead of python3 (some systems link them)

“No module named pip”

Problem: pip is not installed.

Solution:

  • Windows: pip installs automatically with Python
  • macOS/Linux: Install with sudo apt install python3-pip (Ubuntu/Debian) or package manager
  • Verify: pip3 --version or python3 -m pip --version

Virtual environment activation fails (Windows PowerShell)

Problem: PowerShell blocks script execution.

Solution:

Set-ExecutionPolicy -ExecutionPolicy RemoteSigned -Scope CurrentUser

Then try activation again: myenv\Scripts\Activate.ps1

Package installation fails with “Permission denied”

Problem: No write access to system Python directory.

Solution:

  • Use virtual environment (recommended): Create venv and install packages there
  • Or install with --user flag: pip install --user <package>
  • Avoid using sudo pip (can break system Python)

Multiple Python versions installed

Problem: python --version shows old version.

Solution:

  • Use version-specific command: python3.12 --version
  • Update PATH to prioritize new Python
  • Or use py launcher (Windows): py -3.12 --version

Further Resources

Official Python Documentation:

Development Tools:

Community:

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