5. Copyleft Explained The Power of the GPL

(Intro Music Fades In and Out)

Pratyay: Hey there! Welcome back to Tech Bytes with Pratyay—your weekly shortcut to computer science on the go.

We’ve talked about the philosophy of free software. But a philosophy without a way to protect it is just an idea. So, how do you make sure free software stays free? With a brilliant piece of legal engineering. You’ve heard of copyright, right? Well, today we’re meeting its rebellious cousin: copyleft.

Pratyay: Copyleft is the engine of the free software movement. It gives the Four Freedoms their legal force. Without it, a company could take a free program, tweak it, and lock it down as their own proprietary product. Copyleft prevents that. It ensures the freedom you receive is the same freedom you pass on. It’s the legal backbone that holds the entire ecosystem together.

To understand copyleft, you first have to understand copyright. By default, copyright gives the creator full control—an “all rights reserved” system that restricts others.

Copyleft flips that idea. It’s a legal hack that uses copyright law to guarantee sharing instead of blocking it. When a creator uses a copyleft license, they give everyone the Four Freedoms—but with one important condition. This is all spelled out in the GNU General Public License, or GPL.

The heart of the GPL is the “share-alike” rule: you can modify the code however you want, but if you distribute your version, it must also be licensed under the GPL. In short—you have to pass the same freedom forward. It makes freedom viral, in the best possible way.

Pratyay: Think of it like a magic recipe at a community potluck.

You bring an amazing dish and leave the recipe next to it. The card says: “You can use this recipe. You can change it. You can share it. The only rule is—if you share your new version, you must also share your updated recipe under these same rules.”

This stops anyone from adding a secret ingredient, claiming it as their own, and hiding the recipe. The rule keeps everything open, and everyone benefits from each improvement. The GPL is that magic rule—it keeps the potluck fair and collaborative. A true recipe for success.

Pratyay: The GPL isn’t some niche license; it protects some of the most critical software on the planet. The Linux kernel, the foundation of the Linux operating system, runs under the GPL. That’s a big reason it’s stayed free and unified for over 30 years. WordPress, which powers much of the web, is GPL. So is Git, the version control system that developers rely on every day.

That “share-alike” rule also explains why many companies are cautious with GPL code. If they mix it into their own proprietary projects, they might have to release their entire codebase to the public.

(Outro Music Fades In Gently)

Pratyay: Wrapping up—copyleft is a clever use of copyright law that ensures software and its derivatives remain free forever. The GNU GPL is its most famous expression, and it’s a cornerstone of the open internet.

That’s your byte-sized note from Tech Bytes with Pratyay. Today we explored a concept that’s quietly protecting the digital world you use every day.

Next week, we’ll flip the perspective. What if you want to share your code with almost no rules? We’ll dive into the world of permissive licenses.

If something clicked for you, don’t forget to follow, like, and share! And tell me—what’s a tech concept you wish was explained better? Let’s bust more tech myths together.