Shulou(Shulou.com)06/02 Report--

I. outline

Overview of 1.Expect

2.Expect installation (underlying language Tcl)

3.Expect basic command

4.Expect execution mode

5.Expect case

I. Overview of Expect

1.Expect is a tool based on TCL language, and Expect is a tool for automatic control and testing. Mainly solve the problem of non-interactive in shell script. It is very helpful for large-scale linux operation and maintenance.

two。 In linux operation and development, we often need to log on to the server remotely. The login process is an interactive process, and Yuyao may enter yes/no password and other information. To simulate this input, you can use an Expect script.

II. Expect installation

1. Mount the CD

two。 Make a local YUM source

Execute the installation command: yum-y intall expect

III. Basic orders

1.send

Send a string to the process to simulate the user's input

This command cannot automatically enter to change the line, and usually add\ r (enter).

2.expect

An internal command of expect determines whether the specified string is included in the last output, and returns it immediately if so, otherwise it will return after waiting for the timeout.

You can only capture the output of processes started by spawn

3.spawn

Start the process and track subsequent interactions

4.interact

Maintain the interactive state after the execution is completed, and hand over the control to the console

5.Timeout

Specify the timeout period. If it expires, you will continue to execute subsequent instructions of the expect script.

Unit is: seconds

Timeout-1 for never timeout

By default, timeout is 10 seconds

6.exp_continue

Allow expect to continue to execute instructions down

7.send_user

Echo command, equivalent to echo

8.$argv parameter array

The Expect script can accept parameters passed from bash, which can be obtained using [lindex $argv n], where n starts at 0 and represents the first, second, and third, respectively. Parameters.

TIP

Expect scripts must end with interact or expect ecof, and expect eof is usually enough to perform automated tasks

Expect eof is really waiting for the end sign. Commands initiated by spawn end with an eof tag that expect eof is waiting for.

Fourth, the implementation of Expect:

Direct execution

V. case

Remote login

Embedded execution

Automatically exit after logging in to remote control

TIP

Explain here. "

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