Linux is a Unix-like, open-source, operating system for computers.

An operating system is an infrastructure of language code that interfaces with the hardware of your computer system. It recognizes your hardware and makes it available to your software programs so that the software runs smoothly on your computer. Software is written then, with the protocols of a specific operating system in mind. An operating system in turn generally only recognizes software that is written to interface with it.

Although Unix is the grand daddy of operating systems, the most recognizable example of an operating system for most users today is Microsoft Windows. But there are key differences between Microsoft Windows and Linux operating systems.

For one, Linux is an open-source operating system. This means the source code for Linux is publicly available for inspection and even improvement. The advantages of open-source products range from the benefits of creative input from programmers all over the world, to security. With the source code readily available in the public domain, open-source products can be vigorously tested by programmers all over the world. This is much more difficult with a closed system like Microsoft Windows because the source code is not publicly available.

Another major difference between Linux and Microsoft Windows is that Linux is based on the Unix operating system, while Windows is a proprietary or stand-alone operating system.

Many people who are considering switching to Linux wonder if their current Windows software will run on Linux. The short answer is no. The Linux operating system was not designed for, or intended to run Windows software. That said, interfaces like WINE, which is free and comes with most distributions of Linux, or paying alternatives like Win4Lin and VMW provide various kinds of solutions for running Windows software on Linux machines with varying results. However, it is the hope of Linux enthusiasts that people will switch to Linux-alternative software, as more applications are written for the Linux environment.

It is unknown how many Linux users exist because registration is not required, but the number is estimated to be in the millions.

Linus Torvalds began building Linux in 1991 when he was an undergraduate student at the University of Helsinki in Finland. He continues to develop Linux with the help of volunteer programmers and hackers. Linux licensing allows the user to freely copy and distribute the software with its source code.