Exploring Expect

The interact Command

All of the uses of Expect so far have been to totally automate a task. However, sometimes this is too rigid. For a variety of reasons you may not want to completely automate a task. A common alternative is to automate some of it and then do the rest manually.

In the previous example, anonymous ftp was used to retrieve files automatically from the site ftp.uu.net. At the beginning of that script was some interaction to identify myself to the ftp server. This consisted of entering the string anonymous\r followed by my email address. Here was the Expect fragment to do it:

expect "Name"
send "anonymous\r"
expect "Password:"
send "[e-mail]\r"

Now consider doing this manually. If you like to browse through the many computers that support anonymous ftp, repeating this little identification scenario can be a nuisance. And it seems rather silly since your computer is perfectly capable of supplying this information. This so-called password is not really a secret password—it is just an email address. Let Expect do this part while you do the browsing.

Expect provides a command that turns control from the script over to you. It is named interact and called as:

interact

When this command is executed, Expect stops reading commands from the script and instead begins reading from the keyboard and the process. When you press keys, they are sent immediately to the spawned process. At the same time, when the process sends output, it is immediately sent to the standard output ...