expect實現自動交互由淺入深
作爲運維人員可以通過Shell可以實現簡單的控制流功能，如：循環、判斷等。但是對於需要交互的場合則必須通過人工來干預，有時候我們可能會需要實現和交互程序如telnet服務器等進行交互的功能。而Expect就使用來實現這種功能的工具。Expect是一個免費的編程工具語言，用來實現自動和交互式任務進行通信，而無需人的干預。
安裝expect,直接yum install expect -y
expect中相關命令
| 命令 | 解釋 |
|---|---|
| spawn | 啓動新的進程 |
| send | 用於向進程發送字符串 |
| expect | 從進程接收字符串 |
| interact | 允許用戶交互 |
| exp_continue | 匹配多個字符串在執行動作後加此命令 |
一般步驟：
啓動expect進程（spawn）--> 接收進程字符串(expect) --> 匹配字符串，成功發送字符串(send)，否則等待 --> 結束
好了就直接步入主題吧，不扯那些沒用的。直接上實例：
一. 入門例子：實現自動登錄
[root@localhost shell.sh]# vim test.exp
#!/usr/bin/expectset
timeout 30
spawn ssh -l root 192.168.1.106
expect {
"(yes/no)?" { send "yes\r" }
"password:" { send "jiajie\r" }
}
interact| 參數 | 解釋 |
|---|---|
| #!/usr/bin/expect | 說明使用的shell環境 |
| set timeout 30 | 設置超時時間，單位爲秒，-1爲沒有限制 |
| spawn ssh... | 需要執行的命令,這裏是ssh登陸命令 |
| expect "(yes/no)?" | 判斷上次輸出結果裏是否包含(yes/no)?的字符串 |
| send "yes\r" | 執行交互動作，接軌上一個命令，如果上面的expect執行成功，則發送yes |
| interact | 執行完成後保持交互狀態，把控制權交給控制檯 |
執行該實例：./test.exp
如果報錯-bash: ./test.exp: Permission denied,給744權限即可。
二. 使用變量：
[root@localhost shell.sh]# vim test.exp
#!/usr/bin/expect
set ip 192.168.1.106
set user root
set password jiajie
set timeout 30
spawn ssh -l $user $ip
expect {
"(yes/no)?" { send "yes\r";exp_continue }
"password:" { send "$password\r" }
}
interactset:設置變量，後面直接變量，通過“$變量名”來調用
三. 使用位置參數：
[root@localhost shell.sh]# vim test.exp
#!/usr/bin/expect
if {$argc!=3} {
send_user "Usage:expect need three arguments:ip user password\n"
exit 1
}
set ip [lindex $argv 0]
set user [lindex $argv 1]
set password [lindex $argv 2]
set timeout 30
spawn ssh -l $user $ip
expect {
"(yes/no)?" { send "yes\r";exp_continue }
"password:" { send "$password\r" }
}
interact[lindex $argv num]：表示位置參數，從num=0開始
send_user: 打印當前提示，相當於shell裏的echo.
四. 執行多個命令：
[root@localhost shell.sh]# vim test.exp
#!/usr/bin/expect
if {$argc!=3} {
send_user "Usage:expect need three arguments:ip user password\n"
exit 1
}
set ip [lindex $argv 0]
set user [lindex $argv 1]
set password [lindex $argv 2]
set timeout 30spawn ssh -l $user $ip
expect {
"(yes/no)?" { send "yes\r";exp_continue }
"password:" { send "$password\r" }
}
expect "]#" { send "useradd jj\r" }
expect "]#" { send "echo jiajie|passwd --stdin jj\r" }
send "exit\r"expect eofexit -onexit {
send_user "useradd jj is successfully.\n"
send_user "Jobs has finished,Goodbye.\n"
}執行後的結果輸出：
[root@localhost shell.sh]# ./test.exp 192.168.1.106 root jiajie spawn ssh -l root [email protected]'s password: Last login: Sat Sep 9 03:47:48 2017 from web [root@localhost ~]# useradd jj [root@localhost ~]# echo jiajie|passwd --stdin jj Changing password for user jj. passwd: all authentication tokens updated successfully. [root@localhost ~]# exitlogout Connection to 192.168.1.106 closed. useradd jj is successfully. Jobs has finished,Goodbye.
send "exit\r":登錄出當前環境。
expect eof：結束expect匹配。
exit -onexit{...}：打印結束的提示信息。
五. shell腳本調用expect(1)
[root@localhost shell.sh]# vim test.sh
#!/bin/bash
ip=$1
user=$2
password=$3
expect <<EOF
set timeout 10
spawn ssh -l $user $ip
expect {
"yes/no" { send "yes\n";exp_continue }
"password" { send "$password\n" }
}
expect "]#" { send "useradd jj\n" }
expect "]#" { send "echo jiajie|passwd --stdin jj\n" }
expect "]#" { send "exit\n" }
expect eof
EOF執行後的輸出結果：
[root@localhost shell.sh]# ./test.sh 192.168.1.106 root jiajie spawn ssh -l root [email protected]'s password: Last login: Sat Sep 9 04:10:46 2017 from web [root@localhost ~]# useradd jj [root@localhost ~]# echo jiajie|passwd --stdin jj Changing password for user jj. passwd: all authentication tokens updated successfully. [root@localhost ~]# exit logout Connection to 192.168.1.106 closed. [root@localhost shell.sh]#
五. shell腳本調用expect(2)
通過shell腳本通過調用expect腳本實現批量認證:
expect腳本：
[root@localhost shell.sh]# vim scp.exp
#!/usr/bin/expect
if {$argc!=3} {
send_user "Usage:expect need three arguments lisk thks:file host dir\n"
exit 1
}
set srcname [lindex $argv 0]
set hostname [lindex $argv 1]
set destname [lindex $argv 2]
set password "jiajie"
spawn scp $srcname root@$hostname:$destnameset
timeout 30
expect {
# -timeout 2
"yes/no" {send "yes\r";exp_continue}
"*password:" {send "$password\r"}
# timeout {puts "expect connect failure,please contact admin.";return}}
expect eofexit -onexit {
send_user "Jobs has finished,Goodbye.\n"
}shell腳本：
[root@localhost shell.sh]# vim scp.sh
#!/bin/bash
if [[ "$#" != "2" ]];then
echo "Usage:$0 src_filename des_filename"
exit 0
fi
IP_LIST=(
192.168.1.106
192.168.1.170
192.168.1.10)
. /etc/init.d/functions
for ip in ${IP_LIST[*]}
do
expect scp.exp $1 $ip $2 &> /dev/null
if [ $? -eq 0 ];then
action "$ip" /bin/true
else
action "$ip" /bin/false
fi
donescp.sh腳本通過調用expect腳本來實現分發功能。執行結果如下：
[root@localhost shell.sh]# sh scp.sh /etc/fstab /tmp/ 192.168.1.106 [ OK ] 192.168.1.170 [ OK ] 192.168.1.10 [FAILED]
因爲並沒有192.168.1.10所有報錯。