Linux-交互式转化批处理工具expect

　　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

安装expect

yum -y install expect

expect 语法：

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

常见选项

-c：从命令行执行expect脚本，默认expect是交互地执行的
-d：可以调试信息

示例：

[root@centos8~]$expect  -c 'expect "\n" {send "pressed enter\n"}'
expect　　　　　　　　　　　　　　　　#交互式输入“expect”  接收
pressed enter　　　　　　　　　　　  #匹配到expect后，会输出“pressed enter”，并换行

[root@centos8~]$expect  -d ssh.exp
expect version 5.45.4
argv[0] = expect  argv[1] = -d  argv[2] = ssh.exp  
set argc 0　　　　　　　　　　　　　　#set 定义变量  格式：set   变量名   变量值
set argv0 "ssh.exp"
set argv ""
executing commands from command file ssh.exp
couldn't read file "ssh.exp": no such file or directory

expect中相关命令

spawn　　 　　　　启动新的进程
expect　　 　　　 从进程接收字符串
send　　 　　　　 用于向进程发送字符串
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

　expect最常用的语法（tcl语言：模式-动作）

单一分支模式语法

[root@centos8~]$expect
expect1.1> expect "hi" {send "You said hi\n"}   #交互式输入时，不能随意编辑，需一次性输入成功
hahiccc
You said hi
expect1.2>

匹配到hi后，会输出“you said hi”，并换行

多分支模式语法：

[root@centos8~]$expect
expect1.1> expect "hi" {send "You said hi\n"}
hahiccc
You said hi
expect1.2> expect "hi" { send "You said hi\n" } "hehe" { send "Hehe yourself\n"} "bye" { send "Good bye\n" }
bye
Good bye
expect1.3> expect "hi" { send "You said hi\n" } "hehe" { send "Hehe yourself\n"} "bye" { send "Good bye\n" }
hi
You said hi
expect1.4> expect "hi" { send "You said hi\n" } "hehe" { send "Hehe yourself\n"} "bye" { send "Good bye\n" }
hehe
Hehe yourself

匹配hi，hehe，bye任意字符串时，执行相应输出。

示例：自动登录

[root@centos8/data]$vim expect.logon 
    #!/usr/bin/expect
    # 
    #
    spawn ssh root@10.0.0.77
    expect {
            "yes/no" { send "yes\n";exp_continue }
            "password" { send "密***码\n" }
    }
    interact
[root@centos8/data]$ll expect.logon 
-rw-r--r-- 1 root root 141 Apr 27 15:30 expect.logon
[root@centos8/data]$chmod +x expect.logon 
[root@centos8/data]$ll
total 4
-rwxr-xr-x 1 root root 141 Apr 27 15:30 expect.logon
[root@centos8/data]$./expect.logon 
spawn ssh root@10.0.0.77
The authenticity of host '10.0.0.77 (10.0.0.77)' can't be established.
ECDSA key fingerprint is SHA256:a8HZZS4TTvzQbF1/XJKDZvry1Lwa+9/jYIYXRPwqfIk.
Are you sure you want to continue connecting (yes/no/[fingerprint])? yes
Warning: Permanently added '10.0.0.77' (ECDSA) to the list of known hosts.
root@10.0.0.77's password: 
Last login: Wed Apr 27 15:05:01 2022 from 10.0.0.1