Learn Python Programming

Python Directory and Files Management

Python provides the os, shutil, and pathlib modules for creating, reading, moving, and deleting files and directories.

Reading and Writing Files

# Writing to a file
with open("output.txt", "w") as f:
    f.write("Hello, World!\n")
    f.write("Second line\n")

# Reading entire file
with open("output.txt", "r") as f:
    content = f.read()
    print(content)

# Reading line by line (memory efficient for large files)
with open("output.txt") as f:
    for line in f:
        print(line.strip())

# Appending to a file
with open("output.txt", "a") as f:
    f.write("Appended line\n")

# Reading into a list of lines
with open("output.txt") as f:
    lines = f.readlines()
    print(lines)  # ["Hello, World!\n", "Second line\n", ...]

Working with Directories (os module)

import os

# Current working directory
print(os.getcwd())  # /home/user/project

# List directory contents
files = os.listdir(".")
print(files)  # ["main.py", "data", "README.md"]

# Create a directory
os.mkdir("new_folder")           # single directory
os.makedirs("path/to/nested", exist_ok=True)  # nested, no error if exists

# Check if path exists
print(os.path.exists("output.txt"))     # True
print(os.path.isfile("output.txt"))     # True
print(os.path.isdir("new_folder"))      # True

# Get file information
size = os.path.getsize("output.txt")    # file size in bytes
print(f"File size: {size} bytes")

# Rename a file or directory
os.rename("old_name.txt", "new_name.txt")

# Remove file and directory
os.remove("temp.txt")            # delete a file
os.rmdir("empty_folder")         # delete empty directory only

pathlib — Modern Path Handling (Python 3.4+)

from pathlib import Path

# Create path objects
current = Path(".")
home = Path.home()
config = home / ".config" / "myapp" / "settings.json"

# Path properties
p = Path("/home/user/documents/report.pdf")
print(p.name)       # "report.pdf"
print(p.stem)       # "report"
print(p.suffix)     # ".pdf"
print(p.parent)     # /home/user/documents
print(p.parts)      # ("/", "home", "user", "documents", "report.pdf")

# Check existence
print(config.exists())     # True/False
print(config.is_file())    # True/False
print(config.is_dir())     # False

# Create directories
Path("data/raw").mkdir(parents=True, exist_ok=True)

# Read and write files
path = Path("greeting.txt")
path.write_text("Hello from pathlib!")
content = path.read_text()
print(content)  # "Hello from pathlib!"

# Iterate directory contents
for item in Path(".").iterdir():
    print(f"{"DIR " if item.is_dir() else "FILE"} {item.name}")

# Glob pattern matching
for py_file in Path("src").glob("**/*.py"):  # recursive
    print(py_file)

Copying, Moving, and Deleting (shutil)

import shutil

# Copy a file
shutil.copy("source.txt", "backup.txt")          # copy file
shutil.copy2("source.txt", "backup.txt")         # copy with metadata

# Copy entire directory
shutil.copytree("src_folder", "dst_folder")

# Move file or directory
shutil.move("old_location/file.txt", "new_location/file.txt")

# Delete directory and all contents (be careful!)
shutil.rmtree("folder_to_delete")

# Get disk usage
total, used, free = shutil.disk_usage("/")
print(f"Free space: {free // (1024**3)} GB")

Practical Examples

# Find all files larger than 1MB
from pathlib import Path

def find_large_files(directory, min_size_mb=1):
    min_bytes = min_size_mb * 1024 * 1024
    large_files = []
    for f in Path(directory).rglob("*"):
        if f.is_file() and f.stat().st_size > min_bytes:
            size_mb = f.stat().st_size / (1024 * 1024)
            large_files.append((f, size_mb))
    return sorted(large_files, key=lambda x: x[1], reverse=True)

for path, size in find_large_files(".", min_size_mb=0.5):
    print(f"{size:.1f} MB - {path}")

# Organize files by extension
import shutil
from pathlib import Path

def organize_downloads(folder):
    categories = {
        "Images": [".jpg", ".png", ".gif", ".svg"],
        "Documents": [".pdf", ".docx", ".txt", ".xlsx"],
        "Videos": [".mp4", ".avi", ".mkv"],
        "Code": [".py", ".js", ".html", ".css"],
    }
    for file in Path(folder).iterdir():
        if file.is_file():
            for category, extensions in categories.items():
                if file.suffix.lower() in extensions:
                    dest = Path(folder) / category
                    dest.mkdir(exist_ok=True)
                    shutil.move(str(file), str(dest / file.name))
                    break

• Always use with open() to ensure files are properly closed after use.
• Prefer pathlib.Path over os.path for cleaner, more readable path code.
• Use shutil for copying, moving, and deleting entire directories.
• Use exist_ok=True with mkdir() to avoid errors if directory exists.
• Use .rglob("pattern") or .glob("**/pattern") for recursive file search.