如何在powershell中选择已经匹配的行之后的第一个匹配行？

Question

我正在尝试使用 powershell 从powercfg 的输出中查询一些 Windows 电源设置。我有足够的信息将范围缩小到设置的子组，但在文本块中我仍然需要使用 GUID 找到匹配的设置，然后我需要提取设置的当前设置值。我可以使用Select-String -Context 实现这一点，但它不是动态的，因此容易出错。我正在寻找一种更简洁的方法来提取价值。

这是我拥有的文本块的示例（存储在$block）：

Power Scheme GUID: 381b4222-f694-41f0-9685-ff5bb260df2e  (Balanced)
  GUID Alias: SCHEME_BALANCED
  Subgroup GUID: 238c9fa8-0aad-41ed-83f4-97be242c8f20  (Sleep)
    GUID Alias: SUB_SLEEP
    Power Setting GUID: 29f6c1db-86da-48c5-9fdb-f2b67b1f44da  (Sleep after)
      GUID Alias: STANDBYIDLE
      Minimum Possible Setting: 0x00000000
      Maximum Possible Setting: 0xffffffff
      Possible Settings increment: 0x00000001
      Possible Settings units: Seconds
    Current AC Power Setting Index: 0x00000708
    Current DC Power Setting Index: 0x00000384

    Power Setting GUID: 94ac6d29-73ce-41a6-809f-6363ba21b47e  (Allow hybrid sleep)
      GUID Alias: HYBRIDSLEEP
      Possible Setting Index: 000
      Possible Setting Friendly Name: Off
      Possible Setting Index: 001
      Possible Setting Friendly Name: On
    Current AC Power Setting Index: 0x00000001
    Current DC Power Setting Index: 0x00000001

    Power Setting GUID: 9d7815a6-7ee4-497e-8888-515a05f02364  (Hibernate after)
      GUID Alias: HIBERNATEIDLE
      Minimum Possible Setting: 0x00000000
      Maximum Possible Setting: 0xffffffff
      Possible Settings increment: 0x00000001
      Possible Settings units: Seconds
    Current AC Power Setting Index: 0x00002a30
    Current DC Power Setting Index: 0x00002a30

    Power Setting GUID: bd3b718a-0680-4d9d-8ab2-e1d2b4ac806d  (Allow wake timers)
      GUID Alias: RTCWAKE
      Possible Setting Index: 000
      Possible Setting Friendly Name: Disable
      Possible Setting Index: 001
      Possible Setting Friendly Name: Enable
      Possible Setting Index: 002
      Possible Setting Friendly Name: Important Wake Timers Only
    Current AC Power Setting Index: 0x00000001
    Current DC Power Setting Index: 0x00000001

假设我想提取 Allow hybrid sleep 的 AC 值，在本例中为 0x00000001。我有 setting_guid 可以插入到查询字符串中。

现在我正在使用这段代码来动态提取特定设置的值：

$block = powercfg /q #{scheme_guid} #{sub_guid}
$setting = $block | Select-String -Pattern #{setting_guid} -Context 0, 8 | %{$_.Context.PostContext}
$line = $setting | Select-String -Pattern 'Current #{ac_or_dc} Power Setting Index'
$line -match 'Current #{ac_or_dc} Power Setting Index: (?<value>0x.{8})'
Write-Output ([int]$matches['value'])

目前这很好用，但硬编码的-Context 0, 8 并不是很理想，因为有时块可能很短或很长，我的查询将无法提取值，或者它会从错误的行中检索。 我希望找到一种更简洁的方法来做到这一点，最好是程序化和人类可读的（regex 只要有意义就可以）。

Answer 1

如果我们希望使用正则表达式来完成此任务，我们可能希望从传递换行符的表达式开始，类似于以下：

Allow hybrid sleep[\s\S]+?Current DC Power Setting Index:\s+(.+)\s
Allow hybrid sleep[\s\S]+?Current DC Power Setting Index:\s+(.+)
Allow hybrid sleep[\w\W]+?Current DC Power Setting Index:\s+(.+)\s
Allow hybrid sleep[\d\D]+?Current DC Power Setting Index:\s+(.+)

我们想要的输出将在这个捕获组中：(.+)。

Demo

正则表达式

如果不需要此表达式并且您希望对其进行修改，请访问此链接regex101.com。

正则表达式电路

jex.im 可视化正则表达式：

Answer 2

这样怎么样……

$PowerData = @'
Power Scheme GUID: 381b4222-f694-41f0-9685-ff5bb260df2e  (Balanced)
  GUID Alias: SCHEME_BALANCED
  Subgroup GUID: 238c9fa8-0aad-41ed-83f4-97be242c8f20  (Sleep)
    GUID Alias: SUB_SLEEP
    Power Setting GUID: 29f6c1db-86da-48c5-9fdb-f2b67b1f44da  (Sleep after)
      GUID Alias: STANDBYIDLE
      Minimum Possible Setting: 0x00000000
      Maximum Possible Setting: 0xffffffff
      Possible Settings increment: 0x00000001
      Possible Settings units: Seconds
    Current AC Power Setting Index: 0x00000708
    Current DC Power Setting Index: 0x00000384

    Power Setting GUID: 94ac6d29-73ce-41a6-809f-6363ba21b47e  (Allow hybrid sleep)
      GUID Alias: HYBRIDSLEEP
      Possible Setting Index: 000
      Possible Setting Friendly Name: Off
      Possible Setting Index: 001
      Possible Setting Friendly Name: On
    Current AC Power Setting Index: 0x00000001
    Current DC Power Setting Index: 0x00000001

    Power Setting GUID: 9d7815a6-7ee4-497e-8888-515a05f02364  (Hibernate after)
      GUID Alias: HIBERNATEIDLE
      Minimum Possible Setting: 0x00000000
      Maximum Possible Setting: 0xffffffff
      Possible Settings increment: 0x00000001
      Possible Settings units: Seconds
    Current AC Power Setting Index: 0x00002a30
    Current DC Power Setting Index: 0x00002a30

    Power Setting GUID: bd3b718a-0680-4d9d-8ab2-e1d2b4ac806d  (Allow wake timers)
      GUID Alias: RTCWAKE
      Possible Setting Index: 000
      Possible Setting Friendly Name: Disable
      Possible Setting Index: 001
      Possible Setting Friendly Name: Enable
      Possible Setting Index: 002
      Possible Setting Friendly Name: Important Wake Timers Only
    Current AC Power Setting Index: 0x00000001
    Current DC Power Setting Index: 0x00000001
'@ 

[regex]::Matches($PowerData,'(?s)hybrid.*?DC').Value | 
ForEach {[regex]::Matches($PSitem,'Current AC Power Setting Index.*').Value}

# Results

Current AC Power Setting Index: 0x00000001

或者

Clear-Host; (((Get-Content -Path '.\PowerDataTemplate.txt')) -match 'hybrid|AC')#[3]

<#
Current AC Power Setting Index: 0x00000708
Power Setting GUID: 94ac6d29-73ce-41a6-809f-6363ba21b47e  (Allow hybrid sleep)
    GUID Alias: HYBRIDSLEEP
Current AC Power Setting Index: 0x00000001
Current AC Power Setting Index: 0x00002a30
Power Setting GUID: bd3b718a-0680-4d9d-8ab2-e1d2b4ac806d  (Allow wake timers)
Current AC Power Setting Index: 0x00000001
#>

Clear-Host; (((Get-Content -Path '.\PowerDataTemplate.txt')) -match 'hybrid|AC')[3]
# Current AC Power Setting Index: 0x00000001

Clear-Host; [regex]::matches($(Get-Content -Path 'variable:\PowerData'),'.*hybrid.*|.*AC.*').Value

<#
Current AC Power Setting Index: 0x00000708
Power Setting GUID: 94ac6d29-73ce-41a6-809f-6363ba21b47e  (Allow hybrid sleep)
Current AC Power Setting Index: 0x00000001
Current AC Power Setting Index: 0x00002a30
Current AC Power Setting Index: 0x00000001
#>


Clear-Host; [regex]::matches($(Get-Content -Path 'variable:\PowerData'),'.*hybrid.*|.*AC.*').Value[2]
# Current AC Power Setting Index: 0x00000001

或者在 PowerShellv5x 中，您可以通过字符串转换模板使用 ConvertFrom-String 或 ConvertFrom-StringData cmdlet。

https://docs.microsoft.com/en-us/powershell/module/microsoft.powershell.utility/convertfrom-stringdata?view=powershell-6

https://docs.microsoft.com/en-us/powershell/module/microsoft.powershell.utility/convertfrom-string?view=powershell-5.1

OP 更新

我对此有更多的了解，如果您所追求的只是一个特定的设置，那么为什么不直接要求它呢。例如。

# Get only (Allow hybrid sleep)
powercfg.exe query SCHEME_MIN SUB_SLEEP HYBRIDSLEEP

# Get only the AC setting
(powercfg.exe query SCHEME_MIN SUB_SLEEP HYBRIDSLEEP) -match 'Current AC Power Setting Index'

 # Results
 Current AC Power Setting Index: 0x00000000