From Bash to Z Shell: Conquering the Command Line

PART 3Extending the Shell

In this third part of the book, we show you how to bring together many of the shell features described in the previous two parts to build simple programs. We then demonstrate creative ways in which you can apply this knowledge to extend components of the shell. We pay particular attention to the ways in which you can enhance the abilities of the shell's line editor and completion system.

CHAPTER 12Variables

A variable is a named placeholder for a value. Whenever you want the shell to remember something, you can store it in a variable. As an analogy, imagine that a variable is a box; the variable's name would be the label on the box.

We have already made quite extensive use of variables in this book. In this chapter ...