Linux is a freely-distributable, independent Unix-like operating system for x86, Motorola 68k, Digital Alpha, Sparc, Mips, and Motorola PowerPC machines. It is an implementation of the POSIX specification with which all true versions of Unix comply. The Linux kernel uses no code from AT&T or any other proprietary source, and much of the software available for Linux is developed by the Free Software Foundation's GNU project.
It supports a wide range of software, including X Windows, Emacs, TCP/IP networking (including SLIP/PPP/ISDN), the works. Many people have executed benchmarks on 80486 Linux systems and found them comparable with mid-range workstations from Sun and Digital.
Linux (often pronounced with a short ``i'' and with the first syllable stressed -- but I perfer the long ``i'' like eye sound just like UNIX with the long ``u'' Line-nucks) is available over the Internet from hundreds of ftp sites, and from various vendors on floppies or on CD-ROM.
The Linux kernel is covered by the GNU Public License (GPL), and is usually bundled with various binaries that comprise a working unix operating system. These software bundles are called ``distributions'' and come in many sizes and arrangements.
Linux is being used today by hundreds of thousands of people all over the world. It is used for software development, networking (intra-office and Internet), and as an end-user platform. Linux has become a cost-effective alternative to expensive Unix systems.