Asynchronous Shell Command Execution in Python: Exploring Alternative Approaches

Running external commands asynchronously from Python scripts is a valuable technique that allows ongoing script execution while external commands perform their tasks. This article explores appropriate methods to achieve this asynchronous behavior, focusing on the use of os.system() and subprocess.Popen.

os.system() and the Ampersand Symbol

Using os.system() with an ampersand (&) at the end of a command can indeed create a detached process that runs asynchronously. However, this method has limitations and is not considered the recommended approach for asynchronous execution.

subprocess.Popen - A Superior Alternative

For reliable asynchronous command execution, subprocess.Popen is the preferred choice. It provides a wide range of control over the child process, allowing you to:

• Create asynchronous processes with Popen()
• Perform tasks concurrently while the child process is active
• Terminate the process with terminate()
• Query its running status with poll()
• Communicate with it using stdin and stdout

Example Usage of subprocess.Popen

from subprocess import Popen
p = Popen(['watch', 'ls'])  # Replace with your command
# Other code can run here while the command is executing
p.terminate()  # Stop the process when necessary

Conclusion

While os.system() can offer a basic level of asynchronous execution, subprocess.Popen provides a more robust and flexible solution for controlling and interacting with child processes. Its versatility and ease of use make it the recommended method for asynchronous shell command execution in Python.