When processing text files, the awk language is ideal for handling data extraction, reporting, and data-reformatting jobs. This practical guide serves as both a reference and tutorial for POSIX-standard awk and for the GNU implementation, called gawk. This book is useful for novices and awk experts alike.
In this thoroughly revised edition, author and gawk lead developer Arnold Robbins describes the awk language and gawk program in detail, shows you how to use awk and gawk for problem solving, and then dives into specific features of gawk. System administrators, programmers, webmasters, and other power users will find everything they need to know about awk and gawk.
Read Source: Effective awk Programming, 4th Edition : Universal Text Processing and Pattern Matching»