linux expect
文章目录
- 如何安装expect
- snap方式安装expect:
- 像Xshell那样保存连接信息
- 像XShell那样执行多条命令
- Scp复制文件
- 流程控制
- case-branch
- if-else
- loop
- 函数定义
- 返回脚本控制
- Reference List
如何安装expect
| 环境 | 版本 |
|---|---|
| CentOS | 8 |
| Snap | 2.45.2-1.el8 |
snap方式安装expect:
One build for all Linux and IoT: Snaps work across Linux on any distribution or version. Bundle your dependencies and assets, simplifying installs to a single standard command.
snap是开始称为流行起来了，我看好多都支持这个工具。比yum的优点是将全部依赖放到一个可执行文件里面，这样就不存在依赖版本冲突问题了。就一个二进制文件，干净整洁我喜欢。
请参考：https://snapcraft.io/install/expect/centos
sudo yum install epel-release
sudo yum install snapd
sudo systemctl enable --now snapd.socket
sudo systemctl restart snapd
sudo ln -s /var/lib/snapd/snap /snap
sudo snap install expect
然后snap的expect二进制可执行文件存储在：/snap/bin/
像Xshell那样保存连接信息
#!/snap/bin/expect -f
set timeout -1
spawn ssh -t -o StrictHostKeyChecking=no -o CheckHostIP=no [email protected]
expect "*password:"
# 发送密码
send "your_passwor\r"
interact
-f的意思是从文件读取
像XShell那样执行多条命令
set timeout -1
# 设置提示符，必须设置且匹配，如果你不是root用户，请用$
set prompt "#"
spawn ssh -t -o StrictHostKeyChecking=no -o CheckHostIP=no [email protected]
expect "*password:"
send "your_password_here\r"
expect "$prompt"
send "mkdir -p test2\r"
expect "$prompt"
send "echo hello > test.log\r"
expect "$prompt"
send "hostname -I\r"
# 这两行是非常有必要的，不然会闪退，我也猜不出来为什么
send "exit \r"
expect eof
效果如下：
Scp复制文件
#!/snap/bin/expect -f
set timeout -1
spawn ssh -t -o StrictHostKeyChecking=no -o CheckHostIP=no [email protected]
expect "*password:"
# 发送密码
send "yourpassword\r"
set prompt "#"
expect "$prompt"
send "scp -r -o StrictHostKeyChecking=no -o CheckHostIP=no [email protected]:/root/expect_tst /root \r"
expect {
"*password:" { send "yourpassword\r"}
}
expect "$prompt"
send "exit \r"
expect eof
流程控制
case-branch
if-else测试
#!/bin/bash
let number=$RANDOM
if [ $number -gt 25000 ]; then
echo "What is your favorite topic?"
else
echo "What is your favorite movie?"
fi
read $REPLY
上面文件保存至questions.sh
测试if-else:
#!/snap/bin/expect -f
set timeout -1
spawn ./questions.sh
expect {
# case branch
"*topic?" { send -- "Programming\r" }
"*movie?" { send -- "Star wars\r" }
}
expect eof
效果如下：
[root@localhost if-else]# ./expect.sh
spawn ./questions.sh
What is your favorite movie?
Star wars
if-else
#!/snap/bin/expect -f
set NUM 5
if { $NUM < 5 } {
puts "\Smaller than 5\n"
} elseif { $NUM > 5 } {
puts "\Bigger than 5\n"
} else {
puts "\Equals 5\n"
}
loop
#!/snap/bin/expect -f
set NUM 0
while { $NUM <= 5 } {
puts "\nNumber is $NUM"
set NUM [ expr $NUM + 1 ]
}
puts ""
效果：
[root@localhost if-else]# ./loop.sh
Number is 0
Number is 1
Number is 2
Number is 3
Number is 4
Number is 5
下面的代码效果是一样的
#!/snap/bin/expect -f
for {set NUM 0} {$NUM <= 5} {incr NUM} {
puts "\nNUM = $NUM"
}
puts ""
函数定义
#!/snap/bin/expect -f
proc myfunc { TOTAL } {
set TOTAL [expr $TOTAL + 1]
return "$TOTAL"
}
set NUM 0
while {$NUM <= 5} {
puts "\nNumber $NUM"
set NUM [myfunc $NUM]
}
效果和上面一样输出1-5.
返回脚本控制
有些交互你在脚本里是不想写的，比如密码，下面一个例子在你输入密码后，再输入@@返回脚本控制。
#!/bin/bash
echo "Hello, who are you?"
read $REPLY
echo "What is you password?"
read $REPLY
echo "What is your favorite topic?"
read $REPLY
上面的脚本要求用户输入三个值，第二个值要求用户输入密码：
#!/snap/bin/expect -f
set timeout -1
spawn ./interact.sh
expect "Hello, who are you?\r"
send -- "Hi Im Adam\r"
expect "*password?\r"
interact @@ return
send "\r"
expect "*topic?\r"
send -- "Technology\r"
expect eof
Reference List
- expect man page