How to Run External Commands from Python Safely

How can I call an external command from Python as if I had typed it in a shell or command prompt?

coldshadow44 on 2025-10-13

2025-10-14

The recommended way in modern Python is to use the subprocess module, which is safe and flexible.

Python 3.5+ Example with subprocess.run

import subprocess

# Run 'ls -l' (or any other shell command)

subprocess.run(["ls", "-l"])

Pass the command and arguments as a list of strings.
subprocess.run executes the command, waits for it to finish, and returns a CompletedProcess object.
You can capture the output if needed:

result = subprocess.run(["ls", "-l"], capture_output=True, text=True)

print(result.stdout)

Why Not os.system?

import os

os.system("ls -l")

Python 3.4 and Earlier

If you’re using Python 3.4 or older:

import subprocess

subprocess.call(["ls", "-l"])

subprocess.call is similar to subprocess.run, but does not return a CompletedProcess object.
For more advanced usage, upgrade to Python 3.5+ and use subprocess.run.

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