PythonHow-ToBeginner · 3 min read

How to Run Python Script in Background Easily

To run a python script in the background, you can use the command line with python script.py & on Unix-like systems or start /B python script.py on Windows. Alternatively, use Python's subprocess module to start a script without blocking your main program.

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Syntax

Here are common ways to run a Python script in the background:

Unix/Linux/macOS Terminal: Use python script.py & to run the script in the background.
Windows Command Prompt: Use start /B python script.py to run the script without opening a new window.
Python subprocess module: Use subprocess.Popen(['python', 'script.py']) to start a script asynchronously from another Python program.

bash/python

python script.py &

start /B python script.py

import subprocess
subprocess.Popen(['python', 'script.py'])

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Example

This example shows how to start a Python script in the background using subprocess.Popen. The main program continues running while the background script runs separately.

python

import subprocess
import time

# Start background script
subprocess.Popen(['python', 'background_task.py'])

print('Main program continues...')
for i in range(3):
    print(f'Main program working {i+1}')
    time.sleep(1)

Output

Main program continues... Main program working 1 Main program working 2 Main program working 3

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Common Pitfalls

Common mistakes when running Python scripts in the background include:

Not using & on Unix systems, which keeps the script in the foreground.
Using start python script.py on Windows without /B, which opens a new window.
Not handling output or errors from background scripts, causing silent failures.
Trying to run scripts in background without proper permissions or environment setup.

Always check if your script needs input or produces output and handle those properly.

bash

## Wrong way on Unix (script stays in foreground):
# python script.py

## Right way on Unix:
# python script.py &

## Wrong way on Windows (opens new window):
# start python script.py

## Right way on Windows:
# start /B python script.py

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Quick Reference

Platform	Command to Run Python Script in Background
Unix/Linux/macOS	python script.py &
Windows CMD	start /B python script.py
Python Code	subprocess.Popen(['python', 'script.py'])

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Key Takeaways

Use python script.py & on Unix-like systems to run scripts in background.

Use start /B python script.py on Windows to avoid opening new windows.

Use Python's subprocess.Popen to run scripts asynchronously from code.

Always handle script output and errors to avoid silent failures.

Check permissions and environment when running scripts in background.