See WikiPedia: Linux
Linux (often pronounced LIH-nuhks with a short \"i\") is a Unix-like operating system that was designed to provide personal computer users a free or very low-cost operating system comparable to traditional and usually more expensive WikiPedia:Unix systems. Linux has a reputation as a very efficient and fast-performing system. Linux's kernel (the central part of the operating system) was developed by Linus Torvalds at the University of Helsinki in Finland. To complete the operating system, Torvalds and other team members made use of system components developed by members of the Free Software Foundation for the WikiPedia:GNU_project.
Linux is a remarkably complete operating system, including a graphical user interface, an X Window System, TCP/IP, the Emacs editor, and other components usually found in a comprehensive WikiPedia:Unix system. Although copyrights are held by various creators of Linux's components, Linux is distributed using the WikiPedia:Free_Software_Foundation's copyleft stipulations that mean any modified version that is redistributed must in turn be freely available.
Unlike WikiPedia:Microsoft_Windows and other proprietary systems, Linux is publicly open and extendible by contributors. Because it conforms to the Portable Operating System Interface standard user and programming interfaces, developers can write programs that can be ported to other operating systems. Linux comes in versions for all the major microprocessor platforms including the Intel, PowerPC, Sparc, and Alpha platforms. It's also available on IBM's S/390. Linux is distributed commercially by a number of companies. A magazine, Linux Journal, is published as well as a number of books and pocket references.
Linux is sometimes suggested as a possible publicly-developed alternative to the desktop predominance of WikiPedia:Microsoft_Windows. Although Linux is popular among users already familiar with WikiPedia:Unix, it remains far behind Windows in numbers of users.