Exploring Expect

Preface

This book is a tutorial for Expect, a software suite for automating interactive tools.

Expect has turned out to be very popular. This is good and bad. It’s good because people are able to do things more easily than before and in some cases do things that they would never have even tried. Expect is not simply another language. It is a completely new type of tool that addresses problems that were not even recognized as problems in the past.

The bad news is that since writing Expect, I’ve been plagued by people asking me questions about it. While it was not originally intended to be a rich or complex piece of software, it has admittedly become more sophisticated as various features have been added. But more importantly, the nature of automating interactive programs involves dealing with issues that are quite unlike the issues involved in traditional programming.

While Expect comes with a “man page” (which is quite a misnomer at 25 pages), I continue to get requests for information that does not properly belong there. Often the requests are for examples. Sometimes they are simply for advice. This book is an attempt to write down all of these things and to describe everything in the man page in a tutorial fashion.

This book draws upon the thousands of Expect applications that people have described to me, the common and not-so-common problems that people have discussed with me—and explanations of the limitations—what you can’t do with Expect.

I pull no punches. Expect is not meant ...