Automating repetitive tasks with Python

Demo

Why automate?

Every developer has a set of tasks they repeat daily: renaming files, parsing logs, sending reports, moving data between services. Python is one of the best tools for turning those manual steps into a single command.

In this post I’ll walk through a real example: a script that watches a folder, renames incoming files according to a pattern, and logs every action.

The script

import time
import logging
from pathlib import Path
from watchdog.observers import Observer
from watchdog.events import FileSystemEventHandler

LOG_FILE = Path("watcher.log")
WATCH_DIR = Path("~/Downloads").expanduser()

logging.basicConfig(
    filename=LOG_FILE,
    level=logging.INFO,
    format="%(asctime)s  %(message)s",
    datefmt="%Y-%m-%d %H:%M:%S",
)


class RenameHandler(FileSystemEventHandler):
    def on_created(self, event):
        if event.is_directory:
            return

        src = Path(event.src_path)
        timestamp = time.strftime("%Y%m%d_%H%M%S")
        dst = src.with_name(f"{timestamp}_{src.name}")
        src.rename(dst)
        logging.info(f"Renamed: {src.name} → {dst.name}")
        print(f"[+] {dst.name}")


if __name__ == "__main__":
    observer = Observer()
    observer.schedule(RenameHandler(), str(WATCH_DIR), recursive=False)
    observer.start()
    print(f"Watching {WATCH_DIR} — press Ctrl+C to stop")
    try:
        while True:
            time.sleep(1)
    except KeyboardInterrupt:
        observer.stop()
    observer.join()

Breaking it down

watchdog

watchdog is a cross-platform library that wraps OS-level filesystem events (inotify on Linux, FSEvents on macOS, ReadDirectoryChangesW on Windows). No polling — the OS notifies Python the moment something changes.

Install it with:

pip install watchdog

FileSystemEventHandler

We subclass it and override on_created. Other hooks you can use:

Logging

logging.basicConfig writes every rename to watcher.log with a timestamp. Useful for auditing or debugging later.

Running it as a background service

On Linux/macOS you can use nohup:

nohup python watcher.py &

On Windows, wrap it in a .bat file and schedule it with Task Scheduler, or use NSSM to run it as a Windows service.

What’s next

• Add a config file (config.toml) so the rename pattern is configurable without editing code
• Send a desktop notification via plyer when a file is renamed
• Filter by extension — only rename .pdf files, for example

The full code is available on GitHub.