Man page for apt-get expect Command
This tutorial shows the man page for man expect in linux.
Open terminal with 'su' access and type the command as shown below:
Result of the Command Execution shown below:
expect programmed dialogue with interactive programs, Version 5
expect [ dDinN ] [ c cmds ] [ [ [f|b] ] cmdfile ] [ args ]
Expect is a program that "talks" to other interactive programs according to a script. Following the script, Expect knows what can be expected from a program
and what the correct response should be. An interpreted language provides branching and high level control structures to direct the dialogue. In addition,
the user can take control and interact directly when desired, afterward returning control to the script.
Expectk is a mixture of Expect and Tk. It behaves just like Expect and Tk's wish. Expect can also be used directly in C or C++ (that is, without Tcl). See
The name "Expect" comes from the idea of send/expect sequences popularized by uucp, kermit and other modem control programs. However unlike uucp, Expect is
generalized so that it can be run as a user level command with any program and task in mind. Expect can actually talk to several programs at the same time.
For example, here are some things Expect can do:
o Cause your computer to dial you back, so that you can login without paying for the call.
o Start a game (e.g., rogue) and if the optimal configuration doesn't appear, restart it (again and again) until it does, then hand over control to
o Run fsck, and in response to its questions, answer "yes", "no" or give control back to you, based on predetermined criteria.
o Connect to another network or BBS (e.g., MCI Mail, CompuServe) and automatically retrieve your mail so that it appears as if it was originally
sent to your local system.
o Carry environment variables, current directory, or any kind of information across rlogin, telnet, tip, su, chgrp, etc.
There are a variety of reasons why the shell cannot perform these tasks. (Try, you'll see.) All are possible with Expect.
In general, Expect is useful for running any program which requires interaction between the program and the user. All that is necessary is that the interac
tion can be characterized programmatically. Expect can also give the user back control (without halting the program being controlled) if desired. Simi
larly, the user can return control to the script at any time.
Expect reads cmdfile for a list of commands to execute. Expect may also be invoked implicitly on systems which support the