`os`

The Python os module provides tools for using operating system-dependent functionality, like reading or writing to the file system. It allows you to interface with the underlying operating system in a portable way.

Here’s an example:

Python
      
>>> import os
>>> os.name
'posix'

Key Features

Interacts with the operating system
Manipulates file paths and directories
Provides access to environment variables
Facilitates process management

Frequently Used Classes and Functions

Object	Type	Description
`os.path`	Module	Provides common pathname manipulations
`os.environ`	Mapping	Gives access to environment variables
`os.listdir()`	Function	Lists directory contents
`os.mkdir()`	Function	Creates a directory
`os.remove()`	Function	Removes a file
`os.rename()`	Function	Renames a file or directory
`os.walk()`	Function	Generates file names in a directory tree

Note: Even though os is a module rather than a package, it exports os.path, which is a module object.

Examples

List the contents of a directory:

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>>> os.listdir("path/to/target/directory")

Create and remove a directory:

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>>> os.mkdir("new_dir")

>>> os.rmdir("new_dir")

If the directory doesn’t exist or isn’t empty, then rmdir() raises a FileNotFoundError or an OSError, respectively.

Access an environment variable:

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>>> os.environ["HOME"]
'/home/realpython'

Common Use Cases

Navigating and manipulating the file system
Manipulating file and directory paths
Managing environment variables
Running shell commands from Python scripts
Iterating over files and directories

Note: In modern Python, you should pathlib to manipulate paths instead of using os.path.

Real-World Example

Say that you want to organize a directory by moving all .txt files into a subdirectory called text_files. You can achieve this using the os module:

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>>> import os
>>> os.makedirs("text_files", exist_ok=True)

>>> for filename in os.listdir("."):
...     if filename.endswith(".txt"):
...         os.rename(filename, os.path.join("text_files", filename))
...

>>> os.listdir("text_files")
['file1.txt', 'file2.txt']

In this example, you use the os module to create a new directory and move text files into it, which helps keep the file system organized.

Python 3 "pathlib" Module: Taming The Filesystem

Tutorial

Python's pathlib Module: Taming the File System

Python's pathlib module enables you to handle file and folder paths in a modern way. This built-in module provides intuitive semantics that work the same way on different operating systems. In this tutorial, you'll get to know pathlib and explore common tasks when interacting with paths.

intermediate python

For additional information on related topics, take a look at the following resources: