What are the ways to call external programs in Python

• tinyytopic.com
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• on Mar 23, 2023

There are several ways to call external programs using Python code. Here are a few examples:

The subprocess module: This module provides a way to spawn new processes, connect to their input/output/error pipes, and obtain their return codes. It is a powerful and flexible way to call external programs from Python. Here’s an example:

import subprocess

# Call an external program and capture its output
result = subprocess.run(['ls', '-l'], stdout=subprocess.PIPE)

# Print the output
print(result.stdout.decode())

In this example, the subprocess.run() function is used to call the ls command with the -l option, which lists the contents of the current directory in a long format. The stdout argument is set to subprocess.PIPE, which captures the output of the command. The output is then printed to the console using print().

The os module: This module provides a way to interact with the operating system, including running external programs. Here’s an example:

import os

# Call an external program
os.system('ls -l')

In this example, the os.system() function is used to call the ls command with the -l option. The output is printed directly to the console.

The sh module: This module provides a way to run shell commands from Python. Here’s an example:

import sh

# Call an external program
result = sh.ls('-l')

# Print the output
print(result)

In this example, the sh.ls() function is used to call the ls command with the -l option. The output is captured in a variable and then printed to the console using print(). Note that the sh module requires that the external program be installed on the system and accessible from the shell.