This book is full of examples of shell commands and programs that are designed to be useful in your everyday life as a user, not just to illustrate the feature being explained. In Chapter 4, Basic Shell Programming and onwards, we include various programming problems, which we call tasks, that illustrate particular shell programming concepts. Some tasks have solutions that are refined in subsequent chapters. The later chapters also include programming exercises, many of which build on the tasks in the chapter.
You should feel free to use any code you see in this book and to pass it along to friends and colleagues. We especially encourage you to modify and enhance it yourself.
If you want to try examples but you don't use the Korn shell as your login shell, you must put the following line at the top of each shell script:
If your Korn shell isn't installed as the file /bin/ksh, substitute its pathname in the above.