Introduction 🌟

The os module in Python provides functions to interact with the operating system. It allows you to manage files, directories, system paths, process information, and environment variables.

1. Importing the OS Module 🧱

import os

✔ Now you're ready to interact with the operating system

2. Getting Current Working Directory 📍

import os

print(os.getcwd())

✔ Returns the folder where the script is running

3. Changing Directory 📂

os.chdir("C:/Users/Sathish/Desktop")

4. Listing Files & Folders 📁

files = os.listdir(".")
print(files)

✔ Lists all files/directories in the given path

5. Creating Directories 🏗️

os.mkdir("myfolder")

os.makedirs("parent/child/grandchild")

✔ mkdir → creates one folder
✔ makedirs → creates nested folder structure

6. Removing Directories 🗑️

os.rmdir("myfolder")        # remove empty folder

os.removedirs("parent/child/grandchild")

7. Checking If a Path Exists ✔️❌

print(os.path.exists("myfile.txt"))

8. Joining Paths Safely 🔗

path = os.path.join("folder", "subfolder", "file.txt")
print(path)

✔ Automatically uses the correct separator ("/" or "\")
✔ Cross-platform safe

9. Splitting File Path 🪓

print(os.path.split("folder/file.txt"))

print(os.path.splitext("file.txt"))

10. Renaming Files & Folders ✏️

os.rename("old.txt", "new.txt")

✔ Works for both files and directories

11. Removing Files 🧽

os.remove("file.txt")

12. Get Environment Variables 🌍

print(os.getenv("PATH"))

13. Set Environment Variables (Temporary) 🧪

os.environ["APP_MODE"] = "production"
print(os.environ["APP_MODE"])

✔ Useful for config, secrets, deployment

14. Execute System Commands ⚙️

os.system("echo Hello World")

15. Walk Through a Directory Tree 🌲

for root, dirs, files in os.walk("C:/Users/Sathish"):
    print("Root:", root)
    print("Dirs:", dirs)
    print("Files:", files)
    print()

✔ Powerful for indexing, backups, search tools

16. Get File Size 📏

print(os.path.getsize("file.txt"))  # in bytes

17. Check File or Directory Type 📂📄

print(os.path.isfile("file.txt"))
print(os.path.isdir("myfolder"))

18. Real-World Example — Clean Temporary Files 🧹

import os

folder = "temp"

for file in os.listdir(folder):
    path = os.path.join(folder, file)
    if os.path.isfile(path):
        os.remove(path)
        print("Deleted:", path)

✔ Used in automation scripts

19. Real-World Example — Directory Size Calculator 📦

def folder_size(path):
    size = 0
    for root, dirs, files in os.walk(path):
        for f in files:
            size += os.path.getsize(os.path.join(root, f))
    return size

print(folder_size("."))

20. OS Module Cheat Sheet 📘

Best Practices 💡

Conclusion 🎉

You now fully understand the OS module! Want the next topic? Try Sys, Pathlib, Shutil, Pickle, or Subprocess. Just tell me! 😊