How to Run a Python Script in Linux

hello@linuxize.com (Linuxize) — Thu, 22 Feb 2024 08:30:30 +0100

When you have a Python script ready on a Linux system, the next step is usually straightforward: run it from the terminal. Most of the time you will use python3 script.py, but it also helps to know how to make the file executable, pass arguments, and run modules with -m.

This guide walks through the practical ways to run a Python script in Linux, using current Python 3 conventions and a few common troubleshooting steps along the way.

Syntax Overview

The most common ways to run Python code in Linux are:

txt
python3 script.py [arguments]
./script.py [arguments]
python3 -m module_name [arguments]
python3 -c "code"

If you are inside an activated Python virtual environment , python usually points to that environment’s interpreter. Outside a virtual environment, python3 is the safer default on Linux because the plain python command may be missing or mapped differently across systems.

Quick Reference

Command	Description
`python3 script.py`	Run a script with the Python 3 interpreter
`python3 script.py arg1 arg2`	Run a script and pass command-line arguments
`chmod u+x script.py`	Make a script executable
`./script.py`	Run an executable script with a shebang
`python3 -m module_name`	Run a module as a script
`python3 -c "print('hi')"`	Run one short Python command

Check That Python Is Installed

Before you run any script, make sure Python 3 is available on the system:

Terminal
python3 --version

You should see a version string similar to this:

output

Python 3.12.3

If your system also returns Python 3 for python --version, that command will work too. For Linux instructions in general, python3 is the clearer choice and avoids ambiguity.

Run a Script with `python3`

The simplest method is to pass the script filename to the interpreter.

Create a file named hello.py with the following contents:

hello.pypy
print("Hello, Linux!")

Run it with:

Terminal
python3 hello.py

The output should look like this:

output

Hello, Linux!

This is the most reliable way to run a script because it does not depend on file permissions or a shebang line.

Make the Script Executable with a Shebang

If you plan to run the file directly, add a shebang at the top of the script.

Update hello.py so it starts with:

hello.pypy
#!/usr/bin/env python3

print("Hello, Linux!")

Then make the file executable:

Terminal
chmod u+x hello.py

Now you can run it like this:

Terminal
./hello.py

You should see:

output

Hello, Linux!

For general Linux systems, #!/usr/bin/env python3 is the safer shebang because it looks up python3 in your current PATH. That makes the script more portable across distributions and environments.

Pass Arguments to a Script

Many Python scripts accept arguments from the command line. A simple way to read them is with sys.argv.

Create a file named greet.py:

greet.pypy
import sys

name = sys.argv[1] if len(sys.argv) > 1 else "world"
print(f"Hello, {name}!")

Run the script and pass one argument:

Terminal
python3 greet.py Linuxize

This prints:

output

Hello, Linuxize!

For anything beyond one or two simple arguments, switch to argparse so you can define named options, flags, and help text cleanly.

Run a Module with `python3 -m`

Some Python tools are meant to be run as modules rather than as standalone script files. In those cases, use the -m option instead of pointing to a file directly.

For example, to start a simple HTTP server from the current directory, run:

Terminal
python3 -m http.server 8000

You can also use this pattern for Python’s virtual environment module:

Terminal
python3 -m venv .venv

This form makes sure Python runs the module from the same interpreter you invoked on the command line, which helps avoid confusion when you work across multiple Python installations.

Run One-Off Python Code from the Terminal

If you only need to execute a short command and do not want to create a file first, use -c:

Terminal
python3 -c "print('Hello from the terminal')"

That prints:

output

Hello from the terminal

If you want to test a few lines interactively, start the interpreter instead:

Terminal
python3

Once you see the >>> prompt, you can enter Python code line by line.

Troubleshooting

python3: command not found
Python 3 is either not installed or not in your PATH. Install it from your distribution packages, then verify the installation again with python3 --version.

Permission denied when running ./script.py
The file is not executable yet. Run chmod u+x script.py and make sure the first line is #!/usr/bin/env python3.

The script uses the wrong interpreter
Run the file explicitly with python3 script.py or update the shebang to #!/usr/bin/env python3. On Linux, the plain python command may point to Python 3, Python 2, or may not exist at all, so it is better not to assume.

ModuleNotFoundError appears even though the package is installed
You are likely using a different interpreter from the one where the package was installed. Activate the correct virtual environment if needed, and install packages with python3 -m pip install package_name so pip and python3 refer to the same interpreter.

Conclusion

For day-to-day work on Linux, the two methods you will use most are python3 script.py and an executable script with #!/usr/bin/env python3. If the script depends on third-party packages, pair those patterns with a Python virtual environment so each project keeps its own interpreter and dependencies.

Raghav Maddukuri on Linuxize

How to Run a Python Script in Linux

Syntax Overview #

Quick Reference #

Check That Python Is Installed #

Run a Script with python3 #

Make the Script Executable with a Shebang #

Pass Arguments to a Script #

Run a Module with python3 -m #

Run One-Off Python Code from the Terminal #

Troubleshooting #

Conclusion #

Syntax Overview

Quick Reference

Check That Python Is Installed

Run a Script with `python3`

Make the Script Executable with a Shebang

Pass Arguments to a Script

Run a Module with `python3 -m`

Run One-Off Python Code from the Terminal

Troubleshooting

Conclusion