expect是一种能够按照脚本内容里面设定的方式与交互式程序进行“会话”的程序。根据脚本内容，Expect可以知道程序会提示或反馈什么内容以及 什么是正确的应答。它是一种可以提供“分支和嵌套结构”来引导程序流程的解释型脚本语言。
shell功能很强大,但是不能实现有交互功能的多机器之前的操作,例如ssh和ftp.而expect可以帮助我们来实现.
一,安装expect
yum install expect
其实expect根bash形势上差不多的.
二,实例
1,ssh实现自动登录,并停在登录服务器上
#!/usr/bin/expect -f
set ip [lindex $argv 0 ] //接收第一个参数,并设置IP
set password [lindex $argv 1 ] //接收第二个参数,并设置密码
set timeout 10 //设置超时时间
spawn ssh root@$ip //发送ssh请滶
expect { //返回信息匹配
“*yes/no” { send “yes\r”; exp_continue} //第一次ssh连接会提示yes/no,继续
“*password:” { send “$password\r” } //出现密码提示,发送密码
}
interact //交互模式,用户会停留在远程服务器上面.
运行结果如下:
root@unixnotes:/home/unixnotes# ./test.exp 192.168.1.130 admin
spawn ssh [email protected]
Last login: Fri Sep 7 10:47:43 2012 from 192.168.1.142
[root@linux ~]#
这个例子有统一的接口,根据IP和密码可以连接到不同的机器.如果你嫌输入IP和密码麻烦,看下面的例子:
#!/usr/bin/expect -f
set ip 192.168.1.130
set password admin
set timeout 10
spawn ssh root@$ip
expect {
“*yes/no” { send “yes\r”; exp_continue}
“*password:” { send “$password\r” }
}
interact
运行结果如下:
root@unixnotes:/home/unixnotes# ./web.exp
spawn ssh [email protected]
Last login: Fri Sep 7 12:59:02 2012 from 192.168.1.142
[root@linux ~]#
2,ssh远程登录到服务器,并且执行命令,执行完后并退出
#!/usr/bin/expect -f
set ip 192.168.1.130
set password admin
set timeout 10
spawn ssh root@$ip
expect {
“*yes/no” { send “yes\r”; exp_continue}
“*password:” { send “$password\r” }
}
expect “#*”
send “pwd\r”
send “exit\r”
expect eof
运行结果如下:
root@unixnotes:/home/unixnotes# ./test3.exp
spawn ssh [email protected]
[email protected]’s password:
Last login: Fri Sep 7 14:05:07 2012 from 116.246.27.90
[root@localhost ~]# pwd
/root
[root@localhost ~]# exit
logout
Connection to 192.168.1.130 closed.
3,远程登录到ftp,并且下载文件
#!/usr/bin/expect -f
set ip [lindex $argv 0 ]
set dir [lindex $argv 1 ]
set file [lindex $argv 2 ]
set timeout 10
spawn ftp $ip
expect “Name*”
send “zwh\r”
expect “Password:*”
send “zwh\r”
expect “ftp>*”
send “lcd $dir\r”
expect {
“*file” { send_user “local $_dir No such file or directory”;send “quit\r” }
“*now*” { send “get $dir/$file $dir/$file\r”}
}
expect {
“*Failed” { send_user “remote $file No such file”;send “quit\r” }
“*OK” { send_user “$file has been download\r”;send “quit\r”}
}
expect eof
运行结果如下:
root@unixnotes:/home/unixnotes# ./test2.exp 192.168.1.130 /var/www/www aaa.html
spawn ftp 192.168.1.130
Connected to 192.168.1.130.
220 (vsFTPd 2.0.5)
Name (192.168.1.130:root): zwh
331 Please specify the password.
Password:
230 Login successful.
Remote system type is UNIX.
Using binary mode to transfer files.
ftp> lcd /var/www/www
Local directory now /var/www/www
ftp> get /var/www/www/aaa.html /var/www/www/aaa.html
local: /var/www/www/aaa.html remote: /var/www/www/aaa.html
200 PORT command successful. Consider using PASV.
150 Opening BINARY mode data connection for /var/www/www/aaa.html (66 bytes).
226 File send OK.
66 bytes received in 0.00 secs (515.6 kB/s)
quit aaa.html has been download
221 Goodbye.