11.4 Summary

• The programs provided in this chapter continue on the theme that reading programs is an excellent way to learn Good Programming.
• Using ‘#!’ to make awk programs directly runnable makes them easier to use. Otherwise, invoke the program using ‘awk -f …’.
• Reimplementing standard POSIX programs in awk is a pleasant exercise; awk’s expressive power lets you write such programs in relatively few lines of code, yet they are functionally complete and usable.
• One of standard awk’s weaknesses is working with individual characters. The ability to use split() with the empty string as the separator can considerably simplify such tasks.
• The examples here demonstrate the usefulness of the library functions from Library Functions for a number of real (if small) programs.
• Besides reinventing POSIX wheels, other programs solved a selection of interesting problems, such as finding duplicate words in text, printing mailing labels, and finding anagrams.