linux中expect命令详解

Posted 2020-10-09

expect介绍

expect 是由Don Libes基于Tcl（Tool Command Language ）语言开发的，主要应用于自动化交互式操作的场景，借助Expect处理交互的命令，可以将交互过程如：ssh登录，ftp登录等写在一个脚本上，使之自动化完成。尤其适用于需要对多台服务器执行相同操作的环境中，可以大大提高系统管理人员的工作效率

expect命令

expect语法：

expect [选项][ -c cmds] [ [ -[f|b] ] cmdfile] [ args]

选项

-c：从命令行执行expect脚本，默认expect是交互地执行的

示例：

expect -c ‘expect "\n" {send"pressed enter\n"}

-d：可以输出输出调试信息

示例：

expect -d ssh.exp

expect中相关命令

spawn：启动新的进程

send：用于向进程发送字符串

expect：从进程接收字符串

interact：允许用户交互

exp_continue匹配多个字符串在执行动作后加此命令

 

except最常用的语法(tcl语言:模式-动作)

单一分支模式语法：

expect “hi” {send “You said hi\n"}

匹配到hi后，会输出“you said hi”，并换行

多分支模式语法：

expect"hi" { send "You said hi\n" } \

"hehe"{ send “Hehe yourself\n" } \

"bye"{ send “Good bye\n" }

匹配hi,hello,bye任意字符串时，执行相应输出。等同如下：

expect {

"hi"{ send "You said hi\n"}

"hehe"{ send "Hehe yourself\n"}

"bye"{ send “Good bye\n"}

}

示例

cat ssh1.exp

#!/usr/bin/expect

spawn ssh 192.168.8.100

expect {

"yes/no" { send"yes\n";exp_continue }

"password" { send“magedu\n" }

}

interact

#expect eof

示例:变量

cat ssh2.exp

#!/usr/bin/expect

set ip 192.168.8.100

set user root

set password magedu

set timeout 10

spawn ssh [email protected]$ip

expect {

"yes/no" { send"yes\n";exp_continue }

"password" { send"$password\n" }

}

interact

示例:位置参数

vim ssh3.exp

#!/usr/bin/expect

set ip [lindex $argv 0]

set user [lindex $argv 1]

set password [lindex $argv 2]

spawn ssh [email protected]$ip

expect {

"yes/no" { send"yes\n";exp_continue }

"password" { send"$password\n" }

}

interact

#./ssh3.exp 192.168.8.100 rootmagedu

示例：执行多个命令

cat ssh4.exp

#!/usr/bin/expect

set ip [lindex $argv 0]

set user [lindex $argv 1]

set password [lindex $argv 2]

set timeout 10

spawn ssh [email protected]$ip

expect {

"yes/no" { send"yes\n";exp_continue }

"password" { send"$password\n" }

}

expect "]#" { send"useradd haha\n" }

expect "]#" { send"echo magedu |passwd --stdin haha\n" }

send "exit\n"

expect eof

#./ssh4.exp 192.168.8.100 rootmagedu

示例：shell脚本调用expect

vim ssh5.sh

#!/bin/bash

ip=$1

user=$2

password=$3

expect <<EOF

set timeout 10

spawn [email protected]$ip

expect {

"yes/no" { send"yes\n";exp_continue}

"password" { send"$password\n" }

}

expect "]#" { send"useraddhehe\n" }

expect "]#" { send "echomagedu|passwd--stdinhehe\n" }

expect "]#" { send"exit\n" }

expect eof

EOF

#./ssh5.sh 192.168.8.100 rootmagedus

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