1. Shell脚本实现自动登录

#!/usr/bin/expect -f

set IP 115.22.33.44

set PASSWORD pwdpwd

spawn ssh root@$IP

expect {

"*yes/no" { send "yes\r" }

"*password:" { send "$PASSWORD\r" }

}

interact #交互模式,用户会停留在远程服务器上面

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其中，*password:"是一种模糊匹配：如果终端输出了以"password:"的交互窗口，脚本就自动匹配并执行{send "$PASSWORD\r"}中的内容。\r表示回车执行。

2. 自动登录后执行命令

比如说，登录服务器后要执行一个导出mysql数据库的命令。

首先，在变量部分增加如下内容：

#!/usr/bin/expect -f

set IP 115.22.33.44

set PASSWORD pwdpwd

set DB_HOST localhost

set DB_USER dbuser

set DB_PASS mysqlpwd

set DB_NAME dbname

set SERVER_PATH /root/www

spawn ssh root@$IP

expect {

"*yes/no" { send "yes\r" }

"*password:" { send "$PASSWORD\r" }

}

expect "root@*" {send "cd $SERVER_PATH\r"}

expect "root@*" {send "mysqldump -u$DB_USER -p$DB_PASS -h$DB_HOST -B $DB_NAME > $DB_NAME.sql\r"

expect eof

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3、在expect脚本中使用bash

值得注意的是，上述脚本都引用了#!/usr/bin/expect -f，可以称之为expect脚本。expect和bash是两回事，内部使用的语法也就完全不同了。

有时在expect脚本需要继续执行一些bash，该怎么做呢？比如上面将数据库导出后，下载到本地，导入本地数据库，则需要使用 spawn bash。

#!/usr/bin/expect -f

set IP 115.22.33.44

set USER root

set PASSWORD pwdpwd

set DB_HOST localhost

set DB_USER dbuser

set DB_PASS mysqlpwd

set DB_NAME dbname

set SERVER_PATH /root/www

set LOCAL_PATH /Users/Download

set LOCAL_DB_USER root

set LOCAL_DB_PASS localdbpwd

set prompt {\$ $}

spawn ssh $USER@$IP

expect {

"*yes/no" { send "yes\r" }

"*password:" { send "$PASSWORD\r" }

}

#使用puts而不是echo，来输出信息

puts "login to server: $IP and dump database $DB_NAME"

expect "root@*" {send "cd $SERVER_PATH\r"}

expect "root@*" {send "mysqldump -u$DB_USER -p$DB_PASS -h$DB_HOST -B $DB_NAME > $DB_NAME.sql\r"

expect eof

puts "下载 $DB_NAME.sql 到本地"

spawn scp $USER@$IP:$SERVER_PATH/$DB_NAME.sql $LOCAL_PATH/

expect {

"*yes/no" { send "yes\r" }

"*password:" { send "$PASSWORD\r" }

}

expect eof

puts "导入本地mysql数据库"

spawn /bin/bash

expect -re $prompt

send "cd $LOCAL_PATH\r"

send "mysql -u$LOCAL_DB_USER -p$LOCAL_DB_PASS -e'drop database if exists $DB_NAME;source $TEMP_PATH/$DB_NAME.sql;'\r"

send "exit\r"

expect eof

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