How to Run Python Code (Command Line and IDEs)

If you are new to Python, one of the first things to learn is how to actually run your code.

This page shows you how to:

Run Python in the terminal for quick tests
Run a saved .py file from the command line
Run Python code in common IDEs and editors
Understand when to use interactive mode and when to use script files

If you just want the fastest possible test, try this first:

python --version
python
print("Hello, world!")
exit()

# Save this as hello.py
print("Hello from a file")

# Run the file
python hello.py

If python does not work, try python3 instead. On some systems the Python launcher py also works, such as py hello.py on Windows.

What this page helps you do

After reading this page, you should be able to:

Run Python interactively in a terminal
Run a saved .py file from the command line
Run Python code in an IDE or code editor
Understand the difference between interactive mode and script files

If you have not installed Python yet, see how to install Python on Windows, macOS, and Linux.

Before you run Python code

First, make sure Python is installed.

Open a terminal or command prompt and try one of these commands:

python --version

If that does not work, try:

python3 --version

On Windows, this may also work:

py --version

You should see a version number, such as:

Python 3.12.2

If you get a message like command not found or python is not recognized, one of these is probably true:

Python is not installed
Python is installed but not added to your system PATH
You need to use python3 or py instead of python

Run Python in interactive mode

Interactive mode lets you type Python code one line at a time.

This is useful for:

Quick tests
Trying small examples
Checking how a function works

Start interactive mode

In your terminal, type:

python

Or:

python3

If it works, you will see the >>> prompt. That means Python is ready.

Example:

>>>

Try a simple example

Type this at the >>> prompt:

print("Hello, world!")

Expected output:

Hello, world!

You can also try simple math:

2 + 3

Expected output:

Exit interactive mode

To leave interactive mode:

Type exit() and press Enter
On Windows, press Ctrl+Z, then Enter
On macOS/Linux, press Ctrl+D

If you are learning basic Python syntax, your first Python program: Hello World explained is a good next step.

Run a Python file from the command line

For real programs, you usually save your code in a file ending with .py.

This is called a script file.

Step 1: Create a Python file

Create a file named hello.py and put this code in it:

print("Hello from a file")

Step 2: Open the terminal in the same folder

Your terminal needs to be in the folder that contains hello.py.

Step 3: Run the file

Use one of these commands:

python hello.py

Or:

python3 hello.py

Or on Windows:

py hello.py

Expected output:

Hello from a file

This is the normal way to run saved Python programs.

Example with `input()`

Scripts can also pause and wait for user input.

Save this as name.py:

name = input("What is your name? ")
print("Hello,", name)

Run it:

python name.py

Example session:

What is your name? Sam
Hello, Sam

If you want to understand this line better, see Python input() explained and Python print() explained.

How to open the correct folder in the terminal

A very common beginner problem is being in the wrong folder.

If Python says it cannot open your file, check where your terminal is currently located.

Move to a folder with `cd`

Use cd to change folders:

cd path/to/folder

Example:

cd Desktop/python-practice

Check the files in the current folder

On Windows:

dir

On macOS/Linux:

ls

You should see your Python file listed.

Check your current location

On macOS/Linux:

pwd

On Windows, cd by itself often shows the current folder:

cd

If your file is not in that folder, Python will not find it.

Example problem:

python hello.py

Possible error:

python: can't open file 'hello.py': [Errno 2] No such file or directory

This usually means:

You are in the wrong folder
The file name is wrong
The file was not saved yet

Run Python code in an IDE or code editor

You do not have to use the terminal every time.

Most IDEs and code editors can run Python files with a Run button.

Common beginner tools include:

IDLE
VS Code
PyCharm

The basic process is usually the same

Open your Python file
Make sure the file is saved
Make sure the editor is using a valid Python interpreter
Click Run or use the editor's run shortcut

Important checks

If the Run button does nothing, check these things:

The file is saved
The file name ends with .py
Python is installed
The editor is using the correct Python interpreter
Your code does not contain a syntax error

For example, this code will fail because it is missing a closing parenthesis:

print("Hello"

That causes a SyntaxError: invalid syntax.

This code can also fail because of indentation problems:

name = "Sam"
if name == "Sam":
print("Hi")

That can cause an IndentationError: expected an indented block.

If your code runs in the terminal but not in your editor, the editor may be using a different Python installation.

Interactive mode vs running a script

These two ways of running Python are similar, but they are used for different purposes.

Interactive mode

Interactive mode:

Runs one command at a time
Shows results immediately
Is good for quick testing
Does not automatically save your code

Example:

>>> print("test")
test
>>> 10 * 2
20

Script file

A script file:

Runs all saved code from top to bottom
Can be saved and used again later
Is better for larger programs
Is better for repeatable work

Example hello.py:

print("Hello from a script")
print("This runs from top to bottom")

Expected output:

Hello from a script
This runs from top to bottom

For beginners, interactive mode is great for experiments, but script files are better for real practice.

Expected beginner examples to include

Here are three simple examples you can try right away.

Example 1: Interactive mode

Start Python:

python

Then type:

print("Hello, world!")

Expected output:

Hello, world!

Example 2: Run a saved file

Save this in hello.py:

print("Hello from a file")

Run it:

python hello.py

Expected output:

Hello from a file

Example 3: Script with user input

Save this in ask_name.py:

name = input("What is your name? ")
print("Nice to meet you,", name)

Run it:

python ask_name.py

Example output:

What is your name? Maya
Nice to meet you, Maya

Common problems and quick checks

If Python is not running correctly, check these common problems first.

`python` is not recognized or command not found

Possible causes:

Python is not installed
Python is not in PATH
Your system uses python3 or py instead

Try:

python --version
python3 --version
py --version

Wrong file name or missing `.py` extension

Make sure the file name is exactly correct.

For example, hello.py is not the same as:

Hello.py
hello
hello.py.txt

Running from the wrong folder

Use ls or dir to make sure your file is in the current folder.

Then run it again.

Using `python` when the system needs `python3`

Some systems separate Python 2 and Python 3 commands.

If python hello.py fails, try:

python3 hello.py

Interpreter not selected in the IDE

If the terminal works but your IDE does not, check the selected interpreter in the editor settings.

Syntax errors stop the script

If your script has invalid code, it will stop before finishing.

Common examples include:

Missing :
Missing )
Wrong indentation

If you are stuck, see this beginner guide to debugging Python code.

Beginner debugging commands

These commands help you quickly check what is wrong.

python --version
python3 --version
py --version
pwd
cd path/to/folder
ls
dir
python hello.py
python3 hello.py
py hello.py

These commands can help you answer basic questions:

Is Python installed?
Which command works on this computer?
Am I in the correct folder?
Can Python find my file?

FAQ

Should I use `python` or `python3`?

Use the command that works on your system.

Many Windows systems use python or py
Many macOS and Linux systems use python3

What is the difference between the terminal and an IDE?

The terminal runs commands directly.

An IDE gives you:

A code editor
A Run button
Built-in tools for writing and debugging code

Why does Python say it cannot open my file?

Usually one of these is the cause:

You are in the wrong folder
The file name is wrong
The file was not saved

What does `>>>` mean in Python?

It is the prompt for Python interactive mode.

It means Python is ready for you to type code.

Can I run Python without saving a file?

Yes. Use interactive mode by typing python or python3 in the terminal.

Why does my code work in the terminal but not in my IDE?

Usually:

The IDE is using a different Python interpreter
The file was not saved before running it