Question

我需要运行这 4 个命令才能将新映像启动到设备中：

bcdedit /copy {current} /d "Describe"
bcdedit /set {guid} osdevice vhd=somepath 
bcdedit /set {guid} device vhd=somepath
bcdedit /default {$guid}

为了自动化我的脚本，我想提取作为第一个命令的输出返回的 guid/标识符，并将其作为参数传递给其他 3 个命令。现在，我是这样做的：

$guid = Invoke-Command -ComputerName $comp -Credential $cred -ScriptBlock {cmd /c "bcdedit /copy {current} /d "Describe""}

#output
#$guid = This entry was successfully copied to {xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx}

$guid = $guid.Replace("This entry was successfully copied to {","")
$guid = $guid.Replace("}","")

$path1 = "xxx/xxxx/...."

#passing the guid and path as inputs
Invoke-Command -ComputerName $comp -Credential $cred -ScriptBlock {cmd /c "bcdedit /set {$guid} osdevice vhd=$path1"}
Invoke-Command -ComputerName $comp -Credential $cred -ScriptBlock {cmd /c "bcdedit /set {$guid} device vhd=$path1"}
Invoke-Command -ComputerName $comp -Credential $cred -ScriptBlock {cmd /c "bcdedit /default {$guid} "}

但是，每次出现错误时：

元素数据类型无法识别，或不适用于指定的条目。运行“bcdedit /？”用于命令行帮助。未找到元素

当我在 UI 中手动复制和粘贴路径时，这可以正常工作，但我不确定如何实现自动化。

Answer 1

如 this answer 中对您先前问题的解释，无需使用 cmd /c 来调用 bcdedit - 所需的只是引用包含 { 和 } 的文字参数，因为这些字符在不带引号的情况下使用时，在 PowerShell 中具有特殊含义。
- 通过 cmd /c 调用不仅效率低下（尽管在实践中几乎没有影响），而且还会引入令人头疼的引用问题。^[1]
传递给 Invoke-Command -ComputerName ... 的脚本块远程执行，因此无法访问调用者的变量；从调用者的范围中包含变量值的最简单方法是通过 $using: 范围（请参阅 this answer）。

因此：

$guid = Invoke-Command -ComputerName $comp -Credential $cred -ScriptBlock { 
  bcdedit /copy '{current}' /d "Describe" 
}

# Extract the GUID from the success message, which has the form
# "This entry was successfully copied to {xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx}"
$guid = '{' + ($guid -split '[{}]')[1] + '}'

$path1 = "xxx/xxxx/...."

# Passing the guid and path as inputs, which must
# be done via the $using: scope.
Invoke-Command -ComputerName $comp -Credential $cred -ScriptBlock { 
  bcdedit /set $using:guid osdevice vhd=$using:path1
  bcdedit /set $using:guid vhd=$using:path1
  bcdedit /default $using:guid
}

^{[1] 例如，cmd /c "bcdedit /copy {current} /d "Describe"" 并不像您认为的那样工作；它必须是 cmd /c "bcdedit /copy {current} /d `"Describe`""}

将 guid 和路径作为变量传递给 bcdedit /set

1 个答案: