UNIX is an operating system which has seen substantial growth in its popularity over the last few years and is used by many universities and colleges, as well as in industry. Linux is a UNIX-like operating system for PCs which is freely available and has become a serious alternative to proprietary systems such as Windows. This book is a beginner’s guide for students who have to use UNIX and/or Linux. No prior knowledge of programming is assumed, nor is any experience of using computers. We do, however, expect our audience to have a serious interest in computing, and a typical reader might be a student in the first year of a degree or HND course.
UNIX is more than just a computer operating system: it is a philosophy of programming. Learning UNIX involves becoming familiar not only with the commands it affords the user, but also with the methodology it employs. It is a very powerful tool in the hands of an experienced practitioner, but it can be daunting for the novice. We introduce enough detail for the reader to be able to utilise the facilities in UNIX, but no more.
In 1993 an International Standard was published, known as ‘POSIX.2’, which specifies the constructs and commands that a UNIX system should have available to its users. This book follows that standard. However, POSIX is a ‘minimal’ standard, and most UNIX or Linux systems contain much more. We discuss in this book all the basic constructs and commands of UNIX (as defined in POSIX.2), sufficient for the reader to be able to use each of them, together with some of the more common and useful extensions. We do not delve into any in fine detail; part of the UNIX philosophy is that such information is available online. The reader who requires more sophisticated use of UNIX after reading this book will know how and where to find the extra information they need.
To get the most from this book, you should have access to a UNIX computer system or a PC running Linux, as much of the text relies on your being able to try out examples. If you have a PC running Windows, we discuss in Chapter 3 how you can install Linux on your PC.