5 Simple Methods to Run a Python Script From Another Script: Comprehensive Guide With MicroPython Tips

Nowadays, It is a common need to run a python script from another script, especially when you are working on larger projects or automating tasks. Whether you are building something small project or organizing code in multiple files, it is helpful to know the different ways to make one Python file run another.

In this post, you will come to know about 5 simple methods to run a python script from another script including how it works in MicroPython. I will explain when to use each method and share real code examples you can try right away.

Let’s get started.

1. Run Another Script Using import

The easiest way to reuse code from another Python file is to use import. You can call functions or variables directly from one file to another.

When to use it:

• You want to use specific functions, classes, or variables.
• You want to keep your code clean and modular.

Example:

file1.py

def greet():
    print("Hello from file1!")

file2.py

import file1

file1.greet()

This method runs only when you call a function or access something directly. It doesn’t run the whole file unless it’s designed in that way.

Please make sure that both files are in the same folder, or use Python’s sys.path to set the file location.

2. Use os.system() to Run a Script

The os.system() method runs another script as if you typed it in the terminal.

When to use it:

• You want a quick, simple way to run a separate script.
• You don’t need to interact with the script’s output.

Example:

import os

os.system("python3 script2.py")

This will open and run script2.py in the system shell.

⚠️ Be careful:

• You won’t get return values easily.
• It’s slower and less secure than other options.
• It’s not supported in MicroPython.

3. Use subprocess for More Control

subprocess is a powerful module that lets you run another script and get its output or errors.

When to use it:

• You want to capture output.
• You’re building a production app.
• You need better error handling.

Example:

import subprocess

subprocess.run(["python3", "script2.py"])

You can even capture output like this:

result = subprocess.run(["python3", "script2.py"], capture_output=True, text=True)
print(result.stdout)

This method is more flexible and secure than os.system().

4. Use exec() to Run a Script’s Code

This method reads another file and runs its code directly.

When to use it:

• You need to run dynamic or changing code.
• You don’t mind some security risks.

Example:

with open("script2.py") as file:
    code = file.read()
    exec(code)

⚠️ Warning:

Only use this with python scripts you trust. exec() runs any code it reads, which can be risky if the source isn’t secure.

5. Run A Python Script From Another Script In MicroPython

MicroPython is a lightweight version of Python used in small devices (like Raspberry Pi Pico or ESP32). It doesn’t support subprocess or os.system(), so you need simpler methods to run a python script from another.

Best methods for MicroPython:

1. Use import like this:

import script2
script2.main()

2. Use exec() if you need to run a file directly:

exec(open("script2.py").read())

These options help you to organize code in multiple files even on limited hardware.

When to Use Each Method (Quick Guide)

Method	Best For	Works in MicroPython?
import	Reusing functions or code	✅ Yes
os.system()	Quick shell-like execution	❌ No
subprocess	Advanced control and output	❌ No
exec()	Running full scripts dynamically	⚠️ Partially
MicroPython import	Simple script structure	✅ Yes

Best Practices

• Use import whenever possible. It’s the cleanest and safest method.
• Avoid exec() or os.system() unless you know what you’re doing.
• Stick to subprocess for better control in desktop applications.
• In MicroPython, keep things simple and split code into functions for better reuse.

Final Thoughts

Running one Python script from another can be easy, once you understand the options. Whether you’re working on a desktop app, a microcontroller, or a personal automation project, there’s a method that fits your needs.

To recap:

• Use import to reuse code.
• Use subprocess if you need control.
• Use os.system() for quick tasks.
• Use exec() carefully.
• Use simple import in MicroPython.

Try each method and see which one works best for your project!

💬 Your Turn

Have you tried running Python scripts from other scripts before? Which method do you prefer? Drop a comment below, I would love to hear your experience!