Linux is open source, which means anyone can see, modify, and share its code
Linux is open source software, meaning its source code — the human-readable instructions that make it work — is publicly available for anyone to read, change, and redistribute. You do not need permission from a company to look at how Linux works or to create your own version of it. This is different from Windows or macOS, where the source code is kept private by Microsoft and Apple.
The Linux kernel, which is the core part that makes the operating system run, was created by Linus Torvalds in 1991 and released under a license called the GPL (General Public License). The GPL is a legal agreement that says anyone can use, modify, and share Linux as long as they also share their changes under the same GPL license. This creates a chain where improvements flow back to the community instead of being locked away.
Because Linux is open source, thousands of programmers around the world contribute to it. They fix bugs, add features, and make it more secure. No single company owns Linux or controls what happens to it, though companies like Red Hat, Canonical, and others do package and support different versions of it.
Key Takeaways
- Linux's source code is publicly available and anyone can read it, modify it, or create their own version without asking permission.
- Linux is released under the GPL license, which requires that any changes you make and share must also be open source.
- Thousands of volunteer programmers and paid developers contribute to Linux, making it more secure and feature-rich over time.
- Open source does not mean Linux is free of cost, though many distributions are free to download and use.
- Companies can build products on top of Linux and sell them, as long as they follow the GPL license terms.
What "open source" actually means in practice
Open source is a legal and practical arrangement, not just a marketing term. When software is open source, the developers publish the actual code that runs the program. You can download it, read it line by line, and understand exactly what the software does. This is possible with Linux — you can visit kernel.org right now and download the entire Linux kernel source code.
Being open source also means you can modify the code. If you find a bug, you can fix it yourself. If you want to add a feature, you can write the code for it. You can then use your modified version on your own computer without telling anyone. This freedom is why open source appeals to programmers and organizations that need software to work a specific way.
The catch is the license. Linux uses the GPL, which says that if you share your modified version with others, you must share the source code of your changes too. You cannot take Linux, modify it, and then sell a closed version where people cannot see the code. This requirement keeps the software open for everyone downstream.
How Linux's open source model differs from proprietary software
Proprietary software like Windows or Photoshop is closed source. The company that makes it keeps the source code secret. You can use the software, but you cannot see how it works, modify it, or share your own version. If you find a bug, you have to wait for the company to fix it. If you need a feature, you have to ask the company to add it.
Linux works the opposite way. If you find a bug, you can fix it yourself or wait for someone in the community to fix it. If you need a feature, you can add it or ask the community. The code is transparent, so security researchers can examine it and find vulnerabilities before they become problems. This transparency is one reason Linux powers most of the internet's servers — organizations trust it because they can see exactly what it does.
The trade-off is that open source software often has less polished marketing and fewer dedicated support teams than proprietary software. However, many companies now offer paid support for open source software like Linux, so you can get professional help if you need it.
Why companies use and contribute to open source Linux
You might wonder why companies would contribute to software they do not own or control. The answer is that open source benefits them. Companies like Google, Amazon, and Meta use Linux on millions of servers. By contributing improvements back to Linux, they make sure the software works well for their needs and for everyone else.
Companies also hire developers to work on open source projects. Red Hat, for example, employs hundreds of people who work on Linux and related open source software. These companies make money by offering support, training, and services built on top of open source software, not by selling the software itself.
Open source also reduces costs. Instead of each company writing its own operating system from scratch, they can all build on Linux. This shared effort means better software faster, and companies can focus their money on features that matter to their customers.
Different Linux distributions and open source licensing
Linux itself is just the kernel — the core that manages hardware and runs programs. To make a complete operating system, you need other software too: a file manager, a terminal, a package manager, and many other tools. Different organizations combine the Linux kernel with different sets of these tools to create different distributions.
Ubuntu, Fedora, Debian, and Red Hat Enterprise Linux are all Linux distributions. Each one is open source, but they may include different software and have different release schedules. Some distributions are completely free to download and use. Others, like Red Hat Enterprise Linux, charge for support and updates, but the source code is still open.
All of these distributions must respect the GPL license that covers the Linux kernel. This means they must publish their source code and allow others to modify and redistribute it. However, the other software included in a distribution may have different open source licenses, each with slightly different rules about what you can do with the code.
How to access and use Linux's open source code
If you want to see Linux's source code, you do not need special permission or tools. The Linux kernel source is available at kernel.org, and you can download it as a compressed file. You can also browse it online on sites like GitHub, where developers collaborate on open source projects.
To actually use Linux, you do not need to compile the source code yourself. You can download a Linux distribution like Ubuntu or Fedora, which comes pre-built and ready to install on your computer. These distributions are free to download. If you want to modify Linux or build your own distribution, you can download the source code and compile it yourself, but that requires technical knowledge.
Many people use Linux without ever thinking about the source code. They simply install Ubuntu or another distribution and use it like any other operating system. The open source nature of Linux is a benefit even if you never look at the code — it means the community can fix bugs quickly and add features based on what users need.
Open source does not mean free of charge
A common misunderstanding is that open source means free. Open source refers to the availability of source code, not the price. Many open source programs are free to download and use, including most Linux distributions. However, companies can charge money for open source software if they want to.
Red Hat Enterprise Linux is open source but costs money because Red Hat charges for support, updates, and services. You could take the source code, compile it yourself, and use it for free, but most organizations pay Red Hat because they want professional support and may provide updates.
Similarly, you might pay a company to help you install and configure Linux, even though Linux itself is free. The service and support have a cost, even though the software does not.
Frequently Asked Questions
Can I use Linux for free?
Yes. Most Linux distributions like Ubuntu, Fedora, and Debian are free to download and use. You can install them on as many computers as you want without paying anything. Some distributions include paid support options, but the software itself is free.
Can I sell a product that uses Linux?
Yes, but you must follow the GPL license. If you modify the Linux kernel or other GPL-licensed software, you must make your changes available as open source too. You can sell products and services built on Linux, but you cannot hide the source code of the Linux parts.
Who maintains Linux if no company owns it?
Thousands of programmers maintain Linux, including volunteers and employees of companies like Google, Red Hat, and Canonical. Linus Torvalds oversees the kernel itself and decides which changes get included. Different distributions have their own maintainers who manage their versions of Linux.
Is open source Linux less secure than proprietary software?
Not necessarily. Because the source code is public, security researchers can find and report vulnerabilities quickly. The community can fix problems fast. However, security depends on how well the software is maintained and how quickly patches are released, not just whether the code is open or closed.
What is the GPL license and why does it matter?
The GPL is a legal agreement that says anyone can use, modify, and share open source software, but they must share their changes under the same GPL license. This ensures that improvements to Linux stay open source and benefit everyone. It prevents companies from taking Linux, improving it, and then selling a closed version.