What is Linux?

Linux® is an open source operating system (OS) created by Linus Torvalds in 1991. Today, it has a massive user base, and is used in the world’s 500 most powerful supercomputers. Users gravitate toward it for its versatility and security capabilities, among other reasons. The Linux kernel is maintained by a worldwide community of open source enthusiasts and has hundreds of unique distros.

An OS is the software that directly manages a system’s hardware and resources, like the CPU, memory, and storage. The OS sits between applications and hardware and makes the connections between all your software and the physical resources that do the work.

Humans can interact with computers in many ways. Most people’s primary interaction with their hardware happens through an OS, which helps them access a computer’s core functions. There are lots of OS options, from proprietary software made by large companies to open source projects created and supported by volunteers.

Think about an OS like a car engine. An engine can run on its own, but it becomes part of a functional car when it’s connected with a transmission, axles, and wheels. Without the engine running properly, the car won’t work.

Linux was designed to be similar to UNIX, but has evolved to run on a wide variety of hardware from phones to supercomputers. Every Linux-based OS includes the Linux kernel—which manages hardware resources—and a set of software packages that make up the rest of the operating system. Organizations can also choose to run their Linux OS on a Linux server.

Linux includes some common core components, like GNU tools, among others. These tools give the user a way to manage the resources provided by the kernel, install additional software, configure performance and security settings, and more. All these tools bundled together make up the functional operating system. Because Linux is an open source OS, combinations of software can vary between Linux distributions.

When you use an OS, you mainly give the computer commands in 1 of 2 ways: using a graphical user interface (GUI) or the command line (CLI). A GUI refers to everything you can see and interact with when you boot up your OS, like the menus, windows, and desktop icons. If you can point at it and click on it with a mouse, it's probably part of the GUI. This is the most straightforward way to use an OS, because the most common user actions are represented as part of the GUI. 

More complex tasks typically employ the command line, which gives you direct access to the computer. It's where you tell software to perform complicated or specific hardware actions that GUIs can't handle.

Command lines are available on many operating systems―proprietary and open source. But they're usually associated with Linux, because together command lines and open source software give users unrestricted access to their computers.
 

• Kernel: The base component of the OS. Without it, the OS doesn’t work. The kernel manages the system’s resources and communicates with the hardware. It’s responsible for memory, process, and file management.
• System user space: The administrative layer for system-level tasks like configuration and software installation. The system user space includes the shell—or command line—daemons, processes that run in the background, and the desktop environment.
• Applications: A type of software that lets you perform a task. Applications include everything from desktop tools and programming languages to multiuser business suites. Most Linux distributions offer a central database to search for and download additional applications.

Linux is a free, open source operating system released under the GNU General Public License (GPL). Anyone can run, study, modify, and redistribute the source code, or even sell copies of their modified code, as long as they do so under the same license.

According to the Cloud Native Computing Foundation, Linux has become the largest open source software project in the world. Professional and hobbyist programmers and developers from around the world contribute to the Linux kernel, adding features, finding and fixing bugs and security flaws, live patching, and providing new ideas—all while sharing their contributions back to the community.

Reasons to run Linux are as varied as the people and enterprises using it. A few major themes motivate people to choose Linux over another OS:

• Versatility. Linux is flexible enough to adapt for virtually any need you can imagine. It powers all kinds of technology, from small, data-gathering edge devices to complex, cloud-native applications that the world’s largest companies depend on. And because Linux is open source, it’s easier to avoid being locked in to any 1 vendor’s solution. If a part of your technology stack isn’t working for you, chances are there’s a Linux-based, open source alternative you can use instead. 
• Security. Linux’s modularity is especially beneficial in your approach to security, because you can monitor every aspect of the OS. SELinux has been a part of the Linux kernel since 2003, giving administrators visibility into and granular control over user access and application permissions. It’s 1 aspect of a holistic approach to security that Linux makes possible. 
• Community. A worldwide community of practice around Linux has existed for decades, and thousands of smaller communities have formed around specific projects. That means there’s always someone willing to share ideas, troubleshooting tips, and new innovations. 

Linux is the foundation for the modern IT stack, and Red Hat is one of the leading contributors to the Linux kernel and associated technologies in open source communities. Red Hat® engineers help improve features, reliability, and security to make sure your infrastructure performs optimally and remains stable—no matter your use case and workload.

Red Hat Enterprise Linux provides a standard operating environment for everything your enterprise does in every environment—powering the applications that run your business across bare-metal, virtual, and containerized environments, and in private and public clouds.