PrefacePreface
Unix operating system, developed in the 1960s, is regarded as one of the most powerful operating
systems, due to its portability and usage in almost all kinds of environments. It is the result of the
combined efforts of many people—students, professors, researchers, and commercial companies. It is a
multitasking and multi-user operating system that is portable on several hardware platforms and is very
secure. It provides a rich set of tools and utilities that help administrators, programmers, and users, to
a great extent, in executing their tasks. Besides this, Unix offers the fl exibility of controlling individual
jobs executed by a user.
Since its inception, Unix has been evolving constantly and has given rise to various products such
as Linux, Ubuntu, FreeBSD, SunOS, Solaris, SCO, and AIX. In order to understand and learn these
products that are widely in use, it is imperative for users to have a clear understanding of the root, that
is, the actual Unix operating system—its features, management of devices and fi les, implementation of
security, scheduling of CPU, and memory management.
Nowadays, Unix and its by-products are used as servers and in developing mobile applications. Unix
has also served as a model for the development of the Internet, thus shifting the focus of computers
towards the creation of networks.
ABOUT THE BOOK
The book has been designed to cater to students, teachers, professionals, and developers to help them
learn the fundamental concepts of the Unix operating system. It follows a bottom-up approach, that is,
it explains basic commands and gradually moves towards advanced commands. Similarly, it begins with
small and easy scripts and makes the reader acquainted with the fundamental statements, loops, and
conditional statements in a systematic manner. Gradually, it moves on to explain large, complex, and
critical scripts. The book focuses on advanced Unix commands that perform critical functions such as
setting access permissions, changing ownerships of the fi les, sharing fi les among groups, performing
input/output (I/O) redirections, cutting or slicing the fi le vertically, pasting content, comparing fi les, and
printing documents. It explains in detail the manipulation of processes and signals and the role of system
calls. All the major editors in Unix, namely, stream editor (sed), visual editor (vi), and modeless editor
(emacs) are explained in detail.
The book describes Bourne, Korn, and C shell programming and covers all important topics and
commands associated with these shells. It also includes numerous programming scripts for better
understanding of the three types of shells. The later part of the book includes dedicated chapters
on language development tools (
Yacc, Lex, and M4), text-formatting tools (troff and nroff), and Unix
networking and administration.
KEY FEATURES
The book is packed with numerous student-friendly features that are described here.
• Complete scripts along with their outputs are provided for easy implementation of the concepts learnt.
• Each command is explained with its syntax with the help of multiple examples.
