sed & awk, 2nd Edition

Playing the Game

To write an awk script, you must become familiar with the rules of the game. The rules can be stated plainly and you will find them described in Appendix B, rather than in this chapter. The goal of this chapter is not to describe the rules but to show you how to play the game. In this way, you will become acquainted with many of the features of the language and see examples that illustrate how scripts actually work. Some people prefer to begin by reading the rules, which is roughly equivalent to learning to use a program from its manual page or learning to speak a language by scanning its rules of grammar—not an easy task. Having a good grasp of the rules, however, is essential once you begin to use awk regularly. But the more you use awk, the faster the rules of the game become second nature. You learn them through trial and error—spending a long time trying to fix a silly syntax error such as a missing space or brace has a magical effect upon long-term memory. Thus, the best way to learn to write scripts is to begin writing them. As you make progress writing scripts, you will no doubt benefit from reading the rules (and rereading them) in Appendix B or the awk manpage or The AWK Programming Language book. You can do that later—let’s get started now.