How Can I Run Processes in the Background in Python?

Running Processes in Background in Python

When translating shell scripts to Python, it's often desirable to execute certain processes in the background. This ensures that the processes continue running even after the Python script has completed. The shell command "&" achieves this effect, but how can it be replicated in Python?

The recommended approach is to utilize the subprocess module. This module provides a convenient way to manage background processes.

Using the subprocess Module

To start a process in the background, use the Popen function from the subprocess module:

import subprocess
subprocess.Popen(["ls", "-l"])

This command will launch a shell with the "ls -l" command running in the background.

Prevent Blocking

If you attempt to call .communicate() on the Popen object, the process will block until completion. To avoid this and keep the process running in the background, omit the .communicate() call:

import subprocess
ls_output = subprocess.Popen(["sleep", "30"])

Note: Shell Concept of "Background"

It's important to clarify that "background" in this context refers specifically to keeping the process running after the Python script exits. The process itself is still running in the foreground within Python.

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