Effective awk Programming, 4th Edition

Chapter 11. Practical awk Programs

Chapter 10, A Library of awk Functions, presents the idea that reading programs in a language contributes to learning that language. This chapter continues that theme, presenting a potpourri of awk programs for your reading enjoyment. There are three sections. The first describes how to run the programs presented in this chapter.

The second presents awk versions of several common POSIX utilities. These are programs that you are hopefully already familiar with, and therefore whose problems are understood. By reimplementing these programs in awk, you can focus on the awk-related aspects of solving the programming problems.

The third is a grab bag of interesting programs. These solve a number of different data-manipulation and management problems. Many of the programs are short, which emphasizes awk’s ability to do a lot in just a few lines of code.

Many of these programs use library functions presented in Chapter 10.

Running the Example Programs

To run a given program, you would typically do something like this:

awk -f program -- options files

Here, program is the name of the awk program (such as cut.awk), the options are any command-line options for the program that start with a ‘-’, and the files are the actual datafiles.

If your system supports the ‘#!’ executable interpreter mechanism (see Executable awk Programs), you can instead run your program directly:

cut.awk -c1-8 myfiles > results

If your awk is not gawk, you may instead need to use this:

cut.awk ...