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

This article mainly explains "how to use the expect command in the shell script". Interested friends may wish to have a look. The method introduced in this paper is simple, fast and practical. Now let the editor take you to learn how to use the expect command in the shell script.

Expect usage

Expect is a good command to complete a series of automated command operations. I have a deep experience of using it every time it is so troublesome to enter a password for ssh login. Most fixed command execution can also be operated and executed through expect, which is very convenient.

For the following example, we use expect to complete a series of operations, including reading real-time logs

#! / usr/bin/expectspawn ssh troot@127.0.0.1set timeout 30expect "password" send "123456" send "\ n" set timeout 5expect ": ~ >" send "sudo su -" send "\ n" expect "~ #" send "tail-200f / var/log/nginx/access.log" send "\ n" interact

Spawn is an internal expect command that can only be executed after entering the expect environment, so first make sure that the environment has expect installed.

Expect, my understanding is a bit similar to if's judgment.

Send is the key to be entered when performing a certain step

Interact guarantees that you will not log in. If you do not, you will exit immediately after execution.

For possible delays in execution, I use timeout to delay execution of commands

Use bash expect with #! / bin/bash/usr/bin/expect

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