Running

Python can be run in two common ways:

1. Interactive mode (REPL) for quick experiments.
2. Script mode for running .py files.

Note: You can also run and edit Python code directly on this website in every code snippet interactively.

Quickstart (By OS)

Linux / macOS

1. Open Terminal.

2. Check Python is installed:

   python3 --version
   

3. Start interactive mode (REPL):

   python3
   

4. Run a script file:

   python3 hello.py
   

Windows

1. Open PowerShell or Command Prompt.

2. Check Python is installed (try one of these):

   py --version
   # or
   python --version
   

3. Start interactive mode (REPL):

   py
   # or
   python
   

4. Run a script file:

   py hello.py
   # or
   python hello.py
   

Run Python Interactive Mode (REPL)

Start Python:

# Linux/macOS
python3

# Windows (recommended if available)
py

You will see the >>> prompt. Example:

>>> print("Welcome to Python")
Welcome to Python
>>> 2 + 3
5

>>> is the REPL prompt, not part of Python syntax. Do not type >>> into a .py file or the website code editor.

Use this version in files/editors:

print("Welcome to Python")
print(2 + 3)

Exit REPL with:

• exit()
• Ctrl+D (Linux/macOS)
• Ctrl+Z then Enter (Windows)

Run Python Script File

Create hello.py:

print("Learn Python")
print("at belajarpython.com")

Run it from terminal:

# Linux/macOS
python3 hello.py

# Windows
py hello.py
# or: python hello.py

Optional: Run with IDLE on Windows

If you prefer a GUI editor:

1. Open IDLE (Python 3.x) from the Start menu.
2. Use the shell window for quick commands (>>>).
3. For script files, click File > New File.
4. Save the file as .py, then run it with Run > Run Module (F5).

Command-Line Arguments

Python passes command-line arguments through sys.argv:

import sys

print("Script name:", sys.argv[0])
print("Arguments:", sys.argv[1:])

Run:

# Linux/macOS
python3 app.py one two

# Windows
py app.py one two

Other Ways to Run Python

Python has a few useful command-line options:

Note: In the examples below, replace python with python3 on Linux/macOS, or py on Windows.

• Run a short command:

  python -c "print('Hello from -c')"
  

• Run a module as a script (recommended pattern):

  python -m pip --version
  python -m venv .venv
  python -m http.server 8000
  

• Run a script and stay in interactive mode afterwards:

  python -i app.py
  

Tip: On Windows, the py launcher can select a specific version:

py -3.13 --version
py -3.13 -m pip --version

Interactive Editing and History

In many terminals, the REPL supports command history and basic editing:

• Previous commands: Up/Down arrow
• Move cursor in line: Left/Right arrow

Executable Scripts (Unix-like)

You can make a script directly executable:

#!/usr/bin/env python3
print("Hello from executable script")

Then:

chmod +x hello.py
./hello.py

Source File Encoding

Python 3 uses UTF-8 by default. You can still declare encoding explicitly.

The encoding cookie must be on the first or second line of the file. If you use a shebang, put the encoding cookie on line 2:

#!/usr/bin/env python3
# -*- coding: utf-8 -*-
name = "learn python"
print(name)

Without a shebang, you can keep it on the first line:

# -*- coding: utf-8 -*-
name = "learn python"
print(name)