Python OS Module

by

Introduction

The os module in Python provides functions to interact with the operating system. It allows you to work with files, folders, system paths, and environment variables and execute system commands.

Why Use the os Module?

Task you want to doos Module Feature
Get current directoryos.getcwd()
Change directoryos.chdir()
Create/Remove foldersos.mkdir() / os.rmdir()
List files and foldersos.listdir()
Work with environment variablesos.environ
Join file paths safelyos.path.join()
Delete a fileos.remove()
Run system commandsos.system()

Importing OS Module

import os

Directory Operations

Get the current working directory

import os
print(os.getcwd())

Change working directory

os.chdir("C:/Users")

List all files and folders

print(os.listdir())

Create and Delete Directories

Create a new folder

os.mkdir("myfolder")

Remove a folder (only if empty)

os.rmdir("myfolder")

Create multiple nested directories

os.makedirs("main/subfolder/new")

Remove nested directories

os.removedirs("main/subfolder/new")

File Handling

Delete a file

os.remove("sample.txt")

Rename a file

os.rename("oldname.txt", "newname.txt")

Path Operations (os.path)

FunctionDescription
os.path.join()Safely join folder and file names
os.path.exists()Check if path/file exists
os.path.isdir()Check if the path is file
os.path.isfile()Check if the path is a file
os.path.getsize()Get file size in bytes

Example

# This will join the folder path and file name.
path = os.path.join("folder", "file.txt")

# This will return True if path exists.
print(os.path.exists(path))

# get size of file 
print(os.path.getsize(path))

Environment Variables

View environment variables

print(os.environ)

Fetch a specific variable

print(os.environ.get("PATH"))

Run System Commands

Open Command Prompt / Terminal command

# get list of file and folder in windos current directory.
os.system("dir")     # Windows

# get list of file and folder in linux current directory.
os.system("ls")      # Mac/Linux

Examples of Python OS Module

Create a Folder Only If It Doesn’t Exist

import os

folder = "project_data"

if not os.path.exists(folder):
    os.mkdir(folder)
    print("Folder created")
else:
    print("Folder already exists")

List Files Only (Exclude folders)

import os

for item in os.listdir():
    if os.path.isfile(item):
        print("File:", item)

List Folders Only (Exclude files)

import os

for item in os.listdir():
    if os.path.isdir(item):
        print("Folder:", item)

Recursively List Files from All Subdirectories

import os

path = "C:/Users"
for root, dirs, files in os.walk(path):
    print("Current Path:", root)
    print("Folders:", dirs)
    print("Files:", files)
    print("----------")

Count Number of Files and Folders

import os

files = 0
folders = 0

for item in os.listdir():
    if os.path.isfile(item):
        files += 1
    elif os.path.isdir(item):
        folders += 1

print("Files:", files)
print("Folders:", folders)

Copy File to Another Folder (Using os)

os doesn’t have copy directly, so use system command

import os
os.system("copy source.txt destination\\")   # Windows
os.system("cp source.txt destination/")      # Linux/Mac

Get File Size in KB / MB

import os

file = "example.txt"
size = os.path.getsize(file)  # in bytes

print(size / 1024, "KB")
print(size / (1024*1024), "MB")

Check File Permissions

import os

filepath = "example.txt"

print("Readable:", os.access(filepath, os.R_OK))
print("Writable:", os.access(filepath, os.W_OK))
print("Executable:", os.access(filepath, os.X_OK))

Execute Multiple Commands at Once

import os

os.system("dir && echo Hello World")  # Windows
# os.system("ls; echo Hello World")   # Linux/Mac

Change File Permission (Linux/Mac)

import os

os.chmod("script.sh", 0o755)  # Owner read/write/execute, others read/execute

Leave a Comment