This guide to UNIX and Linux aims to enhance the reader's practical knowledge of these operating systems. It includes useful scripts and workarounds, and a command-reference appendix and glossary. Numerous how-to lists and screen shots illustrate the book's answers. It also covers both expert and novice UNIX/Linux topics. UNIX is a widely-used operating system in the fields of Internet/Intranet and high-end computing, and is the founding OS of the World Wide Web. Its presence is strongest in hospitals, financial institutions and large Fortune-500 corporations. There are many flavours of UNIX from different vendors (for example, Sun/Solaris, HP/UX). Two categories of UNIX exist: UNIX System V and Berkeley Software Distribution (BSD). UNIX System V is the version developed by the creators of UNIX, AT&T Bell Laboratories. With UNIX System 4, AT&T and Sun Microsystems (a prominent force in the UNIX marketplace) merged their two versions of UNIX. UNIX System V is considered the semi-official UNIX standard. Linux is a UNIX clone, free of any commercially-copyrighted software, developed for Intel-based PCs. The operating system was designed to bring UNIX power and flexibility to PCs and mainframes. Linux has grown to become a popular OS choice for PC workstations. Charlie Russel is the author of ABCs of Windows NT Workstation 4 and co-author (with Linda Gause) of SCO Open Server: The Windows Network Solution. Sharon Crawford is the co-author (Andy Rathbone) of Windows NT4 for Dummies. Together Charlie Russel and Sharon Crawford are co-authors of Running Microsoft Windows NT Server 4, Windows NT and UNIX Intranet Secrets, Voodoo UNIX and OS/2 for Windows Users.