sed & awk, 2nd Edition

Preface

This book is about a set of oddly named UNIX utilities, sed and awk. These utilities have many things in common, including the use of regular expressions for pattern matching. Since pattern matching is such an important part of their use, this book explains UNIX regular expression syntax very thoroughly. Because there is a natural progression in learning from grep to sed to awk, we will be covering all three programs, although the focus is on sed and awk.

Sed and awk are tools used by users, programmers, and system administrators—anyone working with text files. Sed, so called because it is a stream editor, is perfect for applying a series of edits to a number of files. Awk, named after its developers Aho, Weinberger, and Kernighan, is a programming language that permits easy manipulation of structured data and the generation of formatted reports. This book emphasizes the POSIX definition of awk. In addition, the book briefly describes the original version of awk, before discussing three freely available versions of awk and two commercial ones, all of which implement POSIX awk.

The focus of this book is on writing scripts for sed and awk that quickly solve an assortment of problems for the user. Many of these scripts could be called “quick-fixes.” In addition, we’ll cover scripts that solve larger problems that require more careful design and development.