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Shell 中的 expect 命令

2020-05-15 09:11  jetwill  阅读(17291)  评论(1编辑  收藏  举报

expect 介绍

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员的工作效率。

expect 安装

[root@ansible ssh]# rpm -qa | grep expect
expect-5.45-14.el7_1.x86_64
[root@ansible ssh]# yum -y install expect

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:输出调试信息   

               示例:expect  -d ssh.exp

          expect中的相关命令 

                spawn:启动新的进程 

                send: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  匹配多个字符串时在执行动作后加此命令 

 

     expect最常用的语法(tcl语言:模式-动作) 

        单一分支模式的语法: 

              expect "hi" { send "You said hi\n" }           匹配到 hi 后,会输出"you said hi",并换行

        多分支模式的语法: 

              expect "hi" { send "You said hi\n" } \ "hehe" { send “Hehe yourself\n" } \ "bye" { send "Goodbye\n" } 

        匹配 hi, hehe, bye 中的任意字符串时, 发送相应字符串。等同于:

              expect { "hi" { send "You said hi\n" } "hehe" { send "Hehe yourself\n" } "bye" { send "Goodbye\n" } } 

自动拷贝文件到远程主机

执行 expect 不能以 `bash file` 的方式来执行        (开启一个子shell进程)

必须通过  `chmod +x file ; ./file`  这样的方式    (不会开启子shell进程, 只在当前shell环境中执行)

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`

示例一

1.安装expect  系统默认没有此命令
   yum install expect

2.创建配置文件
[root@ansible ssh]# vi hosts
192.168.31.134 root root
192.168.31.135 root root
192.168.31.136 root root

3.编写脚本
[root@ansible ssh]# ls
copykey.sh  hosts
[root@ansible ssh]# vi copykey.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

4.给脚本执行权限
  chmod +x copykey.sh

5.执行脚本
   ./copykey.sh
                      

读取配置文件自动执行ssh

示例二

#!/usr/bin/expect
spawn scp /etc/fstab root@192.168.33.129:/root
expect {
     "yes/no" { send "yes\n";exp_continue }
     "password" { send "root\n" }
}
expect eof



[root@centos7 ~]# bash one.expect 
one.expect: line 2: spawn: command not found
couldn't read file "{": no such file or directory
one.expect: line 4: yes/no: No such file or directory
one.expect: line 4: exp_continue: command not found
one.expect: line 5: password: command not found
one.expect: line 6: syntax error near unexpected token `}'
one.expect: line 6: `}'
[root@centos7 ~]# ./one.expect 
spawn scp /etc/fstab root@192.168.33.129:/root
The authenticity of host '192.168.33.129 (192.168.33.129)' can't be established.
RSA key fingerprint is SHA256:FzQU22CgZBnSbmZAuoypliidxPK9PsOFjJwcYUZWk5E.
RSA key fingerprint is MD5:a8:2b:51:c3:dc:09:65:89:78:d2:d5:e0:9f:e9:30:1a.
Are you sure you want to continue connecting (yes/no)? yes
Warning: Permanently added '192.168.33.129' (RSA) to the list of known hosts.
root@192.168.33.129's password: 
fstab

示例三

#!/usr/bin/expect 
  set ip [lindex $argv 0] 
  set user [lindex $argv 1] 
  set password [lindex $argv 2] 
  set timeout 10 
  spawn ssh $user@$ip 
   expect {   
       "yes/no" { send "yes\n";exp_continue }         
       "password" { send "$password\n" } 
    } 
   expect "]#" { send "useradd haha\n" }
   expect "]#" { send "echo aaa|passwd --stdin haha\n" }
   send "exit\n" expect eof 
  #./ssh4.exp 192.168.8.100 root aa

执行多条命令

示例四

#!/bin/bash 
ip=$1  
user=$2 
password=$3 
expect <<EOF  
    set timeout 10 
    spawn ssh $user@$ip 
    expect { 
        "yes/no" { send "yes\n";exp_continue } 
        "password" { send "$password\n" }
    } 
    expect "]#" { send "useradd hehe\n" } 
    expect "]#" { send "echo rrr|passwd --stdin hehe\n" } 
    expect "]#" { send "exit\n" } expect eof 
 EOF  
 #./ssh5.sh 192.168.8.100 root aaa 

shell调用expect

参考: https://www.cnblogs.com/yxh168/p/9028122.html