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介绍

• expect是一个自动化交互套件，主要应用于执行命令和程序时，系统以交互形式要求输入指定字符串，实现交互通信。

expect自动交互流程

• spawn启动指定进程---expect获取指定关键字---send向指定程序发送指定字符---执行完成退出.
• 注意该脚本能够执行的前提是安装了expect
• expect 如果只交互一次如拷贝文件 结尾就使用 expect eof
• 如果需要连续交互如登录远程主机执行各种命令结尾就需使用 interact

安装

yum -y  install expect

常用命令

spawn               交互程序开始后面跟命令或者指定程序
expect              获取匹配信息匹配成功则执行expect后面的程序动作
send exp_send       用于发送指定的字符串信息
exp_continue        在expect中多次匹配就需要用到
send_user           用来打印输出 相当于shell中的echo
exit                退出expect脚本
eof                 expect执行结束 退出
set                 定义变量
puts                输出变量
set timeout         设置超时时间

示例一

• 实现批量免密登录

# 主机清单
[root@k8s-master ~]# vi hosts
192.168.1.8 root rootpwd
192.168.1.9 root rootpwd


# 脚本
[root@k8s-master ~]# vi copyssh.sh

#!/bin/bash
if [ ! -f ~/.ssh/id_rsa ];then
 ssh-keygen -t rsa -P "" -f ~/.ssh/id_rsa
else
 echo "id_rsa has created ..."
fi
#分发到各个节点
while read line
  do
    user=`echo $line | cut -d " " -f 2`
    ip=`echo $line | cut -d " " -f 1`
    passwd=`echo $line | cut -d " " -f 3`
    expect <<EOF
      set timeout 10
      spawn ssh-copy-id $user@$ip
      expect {
        "yes/no" { send "yes\n";exp_continue }
        "password" { send "$passwd\n" }
      }
     expect "password" { send "$passwd\n" }
EOF
  done <  hosts


[root@k8s-master ~]# chmod +x copyssh.sh

[root@k8s-master ~]# ./copyssh.sh 
id_rsa has created ...
spawn ssh-copy-id root@192.168.1.8
/usr/bin/ssh-copy-id: INFO: Source of key(s) to be installed: "/root/.ssh/id_rsa.pub"
/usr/bin/ssh-copy-id: INFO: attempting to log in with the new key(s), to filter out any that are already installed
/usr/bin/ssh-copy-id: INFO: 1 key(s) remain to be installed -- if you are prompted now it is to install the new keys
root@192.168.1.8's password: 

Number of key(s) added: 1

Now try logging into the machine, with:   "ssh 'root@192.168.1.8'"
and check to make sure that only the key(s) you wanted were added.

spawn ssh-copy-id root@192.168.1.9
/usr/bin/ssh-copy-id: INFO: Source of key(s) to be installed: "/root/.ssh/id_rsa.pub"
/usr/bin/ssh-copy-id: INFO: attempting to log in with the new key(s), to filter out any that are already installed
/usr/bin/ssh-copy-id: INFO: 1 key(s) remain to be installed -- if you are prompted now it is to install the new keys
root@192.168.1.9's password: 

Number of key(s) added: 1

Now try logging into the machine, with:   "ssh 'root@192.168.1.9'"
and check to make sure that only the key(s) you wanted were added.