Book excerpt: "Effective AWK Programming" covers every aspect of the AWK 3.0.3 and 3.0.4 language. It offers up-to-date coverage of the POSIX standard for AWK, and distinguishes standard AWK features from GNU AWK-specific features. The author sheds light on "dark corners" of the language, devotes two chapters to example programs, and includes a summary of how the AWK language evolved.