Chapter 1, Power Tools for Editing, is an overview of the features and capabilities of sed and awk.
Chapter 2, Understanding Basic Operations, demonstrates the basic operations of sed and awk, showing
a progression in functionality from sed to awk. Both share a similar command-line syntax, accepting
user instructions in the form of a script.
Chapter 3, Understanding Regular Expression Syntax, describes UNIX regular expression syntax in full
detail. New users are often intimidated by these strange expressions, used for pattern matching. It is
important to master regular expression syntax to get the most from sed and awk. The pattern-matching
examples in this chapter largely rely on grep and egrep.
Chapter 4, Writing sed Scripts, begins a three-chapter section on sed. This chapter covers the basic
elements of writing a sed script using only a few sed commands. It also presents a shell script that
simplifies invoking sed scripts.
Chapter 5, Basic sed Commands, and Chapter 6, Advanced sed Commands, divide the sed command set
into basic and advanced commands. The basic commands are commands that parallel manual editing
actions, while the advanced commands introduce simple programming capabilities. Among the
advanced commands are those that manipulate the hold space, a set-aside temporary buffer.
Chapter 7, Writing Scripts for awk, begins a five-chapter section on awk. This chapter presents the
primary features of this scripting language. A number of scripts are explained, including one that
modifies the output of the ls command.
Chapter 8, Conditionals, Loops, and Arrays, describes how to use common programming constructs
such as conditionals, loops, and arrays.
Chapter 9, Functions, describes how to use awk's built-in functions as well as how to write user-defined
functions.
Chapter 10, The Bottom Drawer, covers a set of miscellaneous awk topics. It describes how to execute
UNIX commands from an awk script and how to direct output to files and pipes. It then offers some
(meager) advice on debugging awk scripts.
Chapter 11, A Flock of awks, describes the original V7 version of awk, the current Bell Labs awk, GNU
awk (gawk) from the Free Software Foundation, and mawk, by Michael Brennan. The latter three all
have freely available source code. This chapter also describes two commercial implementations, MKS
awk and Thomson Automation awk (tawk), as well as VSAwk, which brings awk-like capabilities to
the Visual Basic environment.
Chapter 12, Full-Featured Applications, presents two longer, more complex awk scripts that together
demonstrate nearly all the features of the language. The first script is an interactive spelling checker. The
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