Your First Script

Introduction

A Python script is simply a text file with a .py extension. The Python interpreter reads and executes it from top to bottom. This section covers how to write, save, and run your first script.

Hello, World

The traditional first program in any language — print a message to the screen.

In the Terminal (Interactive Mode)

Python comes with an interactive shell called the REPL (Read-Eval-Print Loop). You can use it to run single lines of code immediately.

python

>>> print("Hello, World!")
Hello, World!

Type exit() or press Ctrl+D to leave the REPL.

As a Script File

Create a file called hello.py and add the following:

print("Hello, World!")

Run it from the terminal:

python hello.py

Output

Hello, World!

Comments

Comments are lines Python ignores — they are there for the reader, not the interpreter. Use them to explain what your code is doing.

# This is a single-line comment
print("Hello!")  # This comment is at the end of a line

"""
This is a multi-line string.
It is often used as a block comment or docstring.
"""

The print() Function

print() outputs values to the terminal. It can print strings, numbers, variables, and more.

print("Hello, World!")
print(42)
print("The answer is", 42)
print("Line one\nLine two")   # \n creates a new line

Output

Hello, World!
42
The answer is 42
Line one
Line two

Running Scripts vs the REPL

	REPL	Script file
Good for	Quick tests, exploring	Real programs, saving work
How to run	Type python	python filename.py
Output shown automatically	✅	Only via print()

Practice Exercises

• Create a file called grade1.py and print your name to the terminal.
• Add a comment above the print statement explaining what it does.
• Print three separate lines of output using three print() calls.
• Print two values in a single print() call separated by a space.