PowerShell识别截取后如何拼接字符

Question

我要转以下输入：

May 13 00:30:00 BBAOMACBOOKAIR2 syslogd[113]: Configuration Notice:
    ASL Module "com.apple.cdscheduler" claims selected messages.
    Those messages may not appear in standard system log files or in the ASL database.
May 13 00:30:00 BBAOMACBOOKAIR2 syslogd[113]: Configuration Notice:
    ASL Module "com.apple.install" claims selected messages.
    Those messages may not appear in standard system log files or in the ASL database.
May 13 00:30:00 BBAOMACBOOKAIR2 syslogd[113]: Configuration Notice:
    ASL Module "com.apple.callhistory.asl.conf" claims selected messages.
    Those messages may not appear in standard system log files or in the ASL database.
May 13 00:30:00 BBAOMACBOOKAIR2 syslogd[113]: Configuration Notice:
    ASL Module "com.apple.authd" sharing output destination "/var/log/asl" with ASL Module "com.apple.asl".
    Output parameters from ASL Module "com.apple.asl" override any specified in ASL Module "com.apple.authd".
May 13 00:30:00 BBAOMACBOOKAIR2 syslogd[113]: Configuration Notice:
    ASL Module "com.apple.mkb" sharing output destination "/private/var/log/keybagd.log" with ASL Module "com.apple.mkb.internal".
    Output parameters from ASL Module "com.apple.mkb.internal" override any specified in ASL Module "com.apple.mkb".

进入以下输出：

May 13 00:30:00 BBAOMACBOOKAIR2 syslogd[113]: Configuration Notice:ASL Module "com.apple.cdscheduler" claims selected messages.Those messages may not appear in standard system log files or in the ASL database.
May 13 00:30:00 BBAOMACBOOKAIR2 syslogd[113]: Configuration Notice:ASL Module "com.apple.install" claims selected messages.Those messages may not appear in standard system log files or in the ASL database.
May 13 00:30:00 BBAOMACBOOKAIR2 syslogd[113]: Configuration Notice:ASL Module "com.apple.callhistory.asl.conf" claims selected messages.Those messages may not appear in standard system log files or in the ASL database.
May 13 00:30:00 BBAOMACBOOKAIR2 syslogd[113]: Configuration Notice:ASL Module "com.apple.authd" sharing output destination "/var/log/asl" with ASL Module "com.apple.asl".Output parameters from ASL Module "com.apple.asl" override any specified in ASL Module "com.apple.authd".
May 13 00:30:00 BBAOMACBOOKAIR2 syslogd[113]: Configuration Notice:ASL Module "com.apple.mkb" sharing output destination "/private/var/log/keybagd.log" with ASL Module "com.apple.mkb.internal".Output parameters from ASL Module "com.apple.mkb.internal" override any specified in ASL Module "com.apple.mkb".

也就是说，缩进行应该连接到前面的非缩进行。

Answer 1

我会首先确定它是一个多行字符串（而不是一个字符串数组），然后使用 RegEx 根据 date/time 标记进行拆分，并且对于每个传递的多行位 trim 一行中的任何空格，并将这些行连接成一行。这可以用这样的东西来完成

$LogText -join "`n" -split '[\r\n]+\s*(?=\w+ \d+ \d+:\d+:\d+)'|
    ForEach-Object {$_.trimstart() -replace '[\r\n]+\s*'}

Answer 2

假设您的 May ... 行没有前导白色space:

如果文件足够小，可以作为一个整体放入内存，合并Get-Content -Raw with the regex-based （根据需要将输出重定向到一个文件；如果输入文本已经在内存中，只需使用它作为左轴）：

(Get-Content -Raw file.log).TrimEnd() -replace '\r?\n\s+', ' '

否则，使用带有 -File 和 -Regex 参数的 switch statement：

& {
  $mergedLine = ''
  switch -Regex -File file.log {
    '^\S' {  # 'May ...' line, no leading whitespace.
      if ($mergedLine) { $mergedLine } # output previous 
      $mergedLine = $_
    }
    default { # Subsequent, indented line (leading whitespace)
      $mergedLine += ' ' + $_.TrimStart()
    }
  }
  $mergedLine # output final merged line
}

注：

为了便于阅读，上面的解决方案放置了一个 space 字符。在合并（连接）线之间；从上面的代码中删除 ' ' 的使用以在没有分隔符的情况下加入它们（如您问题的示例输出中所示）。
您可以将 & { ... } 解决方案传送到 Set-Content for output, though if performance is paramount, you may want to use the System.IO.StreamWriter .NET type for faster writing, as shown in 。

一个等效的基于 awk 的解决方案可以在 this answer 中找到你关于原生 macOS 解决方案的后续问题。

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