How to Automatically Run Python Scripts on File Changes Using Watchdog

Automatically run Python scripts when files change using the Watchdog library. Learn real-time file monitoring for automation, app reloading, and productivity.

Sometimes you don’t need your code to run on a timer—you just want it to react the moment something changes.

That’s exactly what the watchdog library is great for. It’s a simple tool in Python that watches your files and folders in real time and lets you run your own code the second something gets added, updated, or deleted.

It’s super handy for things like syncing data, restarting servers, running automation, or just keeping track of a folder without doing everything manually.

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Think of it like a motion sensor for your files. It doesn’t sit there checking over and over again—it just waits quietly and jumps into action when something happens. That makes it way faster and easier on your computer.

At first, I tried using loops and delays with time.sleep(), but it felt slow. This library helps change things. It took just a few minutes to set up, and from then on, the tool felt fast and responsive.

In our article this week, I’ll walk you through how to set it up, how to watch folders or specific files, and how to run your own functions when changes happen. Once you try it, you’ll probably start finding all sorts of uses for it in your own projects—especially if your work involves files in any way.

Let’s start by installing it. Just run:

pip3 install watchdog

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Now let’s look at some code examples and let watchdog do the watching for you.

This Week’s Watchdog Tips