Python Getting Started

Python Getting Started: Setup, CLI Checks, and First Script

Getting started with Python takes three quick steps: install Python 3, verify your terminal command, and run a .py file. Most macOS and Linux systems ship with Python preinstalled, while Windows users install it from python.org.

On Windows, check the Add Python to PATH box in the installer before clicking install. Skipping that checkbox prevents your terminal from finding the python command later.

Verifying Your Python Installation

Open your terminal or PowerShell window and check the installed version. Run one of the commands below depending on your operating system.

# Windows (PowerShell or Command Prompt)
python --version

# macOS and Linux
python3 --version

If you see Python 3.11.x or newer, your environment is ready. You can also launch the interactive shell (REPL) by typing python with no filename.

Running Code in the REPL vs. a Script File

The interactive shell runs one expression at a time, which helps you test small snippets quickly. For real programs, save your code in a file ending with .py and run it from your terminal.

# Save this file as greet_user.py
user_name = "Samira"
tasks_today = 4

print(f"Hello, {user_name}. You have {tasks_today} tasks today.")

Execute the script from the same folder:

python greet_user.py

Common Mistakes to Avoid

• Typing Python code inside the shell prompt: Commands like python greet_user.py belong in your system terminal, not inside the >>> Python prompt.
• Forgetting to save before running: Editors do not auto-save by default, so save your .py file before re-running it in the terminal.
• Working in the wrong directory: If Python reports No such file or directory, run pwd or cd to move into the folder holding your script.

Frequently Asked Questions

What editor should I use for Python?

VS Code with the official Microsoft Python extension works well for beginners and professionals. PyCharm Community Edition is another solid option with built-in debugging.

How do I exit the Python interactive shell?

Type exit() and press Enter, or press Ctrl+Z then Enter on Windows (Ctrl+D on macOS and Linux).

Should I use a virtual environment right away?

For single learning scripts, the global Python install works fine. Once you install third-party packages with pip, create a project venv to isolate dependencies.