期望在 bash 脚本中

Question

我正在尝试将期望脚本实现为 bash 脚本。请耐心等待，因为我对 bash/expect 还很陌生。

这是按预期工作的期望脚本：

log_user 0

file delete foo.txt

set fh [open foo.txt a]

set servers {xxx@server1 xxx@server2}

foreach s $servers {
spawn ssh $s
expect "password: "
send "PASSWORD\r"
expect "$ "
send "grep "something" /some/log/file.log"
expect "$ " { puts $fh "$expect_out(buffer)"}
send "exit\r"
}

close $fh

现在，我希望将这个期望脚本包含在 bash 脚本中，但它没有按预期工作。

这是我目前所拥有的：

#!/bin/bash

XYZ=$(expect -c "
file delete foo.txt

set fh [open foo.txt a]

set servers {xxx@server1 xxx@server2}

foreach s $servers {
spawn ssh $s
expect "password: "
send "PASSWORD\r"
expect "$ "
send "grep "something" /some/log/file.log"
expect "$ " { puts $fh "$expect_out(buffer)"}
send "exit\r"
}

close $fh
")

echo "$XYZ"

我得到的错误是：

command substitution: line 42: syntax error near unexpected token `('
command substitution: line 42: `expect "$ " { puts $fh "$expect_out(buffer)"}'

我愿意接受任何其他方式来实现这一点！ :)

Answer 1

您可以使用/usr/bin/expect -c 执行expect 命令：

#!/bin/bash

/usr/bin/expect -c ' 

file delete foo.txt

set fh [open foo.txt a]

set servers {xxx@server1 xxx@server2}

foreach s $servers {
spawn ssh $s
expect "password: "
send "PASSWORD\r"
expect "$ "
send "grep "something" /some/log/file.log"
expect "$ " { puts $fh "$expect_out(buffer)"}
send "exit\r"
}

close $fh
'

Answer 2

Bertrand 的回答是解决您的问题的一种方法，但并未解释您所做的问题。

Bash 尝试在双引号字符串中展开变量，因此您的 expect 脚本将在您希望看到 $servers、$s 和 $fh 的位置看到空格。此外，您还有三重嵌套的双引号字符串集，这将导致解析expect 的参数时出现各种问题。

这是一个见仁见智的问题，但我认为当某些东西达到某个程度，它被认为是它自己的程序时，它应该被分离到一个单独的文件中。

#!/usr/bin/expect
log_user 0

file delete foo.txt

set fh [open foo.txt a]

set servers {xxx@server1 xxx@server2}

foreach s $servers {
    spawn ssh $s
    expect "password: "
    send "PASSWORD\r"
    expect "$ "
    send "grep 'something' /some/log/file.log"
    expect "$ " {
        puts $fh "$expect_out(buffer)"
    }
    send "exit\r"
}

close $fh

确保它是可执行的，然后从您的bash 脚​​本中调用它：

#!/bin/bash
/usr/local/bin/my_expect_script

（要真正正确地做到这一点，您应该设置公钥身份验证，然后您可以通过直接从 bash 运行 ssh server "grep 'something' /some/log/file.log" 来完全摆脱期望）