Pythonのチュートリアル：popenの作業ディレクトリを指定して使い方や修正方法を簡単に解説

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python popen working directory

Introduction

In this tutorial, we will learn about the popen function in Python and how to specify the working directory for executing a command. The popen function allows us to run shell commands or scripts from within our Python code. By default, it runs the command in the current working directory, but in some cases, we may want to specify a different working directory. Let’s explore how to do that.

Prerequisites

To follow along with this tutorial, you should have a basic understanding of Python and have Python installed on your machine.

What is popen?
Executing commands in the current working directory
Specifying a different working directory
Summary

1. What is `popen`?

The popen function is a powerful tool in Python that allows us to run shell commands or scripts. It is part of the subprocess module and provides a way to interact with the command-line interface. With popen, we can execute commands and capture their output, retrieve the exit status, and more.

2. Executing commands in the current working directory

By default, when we use popen without specifying the working directory, the command will be executed in the current working directory of our Python script. To demonstrate this, let’s run a simple command using popen:

import subprocess

result = subprocess.Popen("ls", shell=True, stdout=subprocess.PIPE)
output = result.communicate()[0]

print(output.decode())

In the above example, we are running the ls command, which lists all the files and directories in the current working directory. The output is captured and printed to the console.

3. Specifying a different working directory

To specify a different working directory for the command, we can use the cwd parameter of the popen function. This allows us to run the command in a specific directory of our choice. Let’s see an example:

import subprocess

result = subprocess.Popen("ls", shell=True, stdout=subprocess.PIPE, cwd="/path/to/directory")
output = result.communicate()[0]

print(output.decode())

In the above code, we have specified the cwd parameter as “/path/to/directory”, which means the ls command will be executed in that directory. This can be useful when we want to run a command in a different directory than our Python script.

4. Summary

In this tutorial, we have learned about the popen function in Python and how to specify the working directory for executing a command. We have seen how to execute commands in the current working directory by default, and how to specify a different working directory using the cwd parameter. The popen function is a powerful tool that enables us to interact with the command-line interface from within our Python code, giving us flexibility in executing commands.