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