选择字符串正则表达式

Question

我正在使用 foreach 循环搜索大量日志以查找字符串 ($text)，并且当前将整行输出到输出文件 ($logfile)

Get-ChildItem "\\$server\$Path" -Filter "*.log" |select-string -pattern $text |select -expandproperty line |out-file $logfile -append

其中一个日志文件的示例行可能如下所示

May 25 04:08:36.640 2016 AUDITOF GUID 1312.2657.11075.54819.13021094807.198 opened by USER

在哪里$text = "opened by USER"

所有这一切都很好，它会吐出每个包含 $text 的日志文件的每一行，这很棒。

但是.. 我想我想做的是获取日期时间和 GUID 的输出。 Guid 可以更改格式、长度等，但它总是有点，并且总是在 GUID (space) 之后和 (space) opened 之前

简而言之，我正在尝试使用后向（或前向）或匹配来进行正则表达式，以将类似的内容返回到 $logfile

2016 年 5 月 25 日 04:08:36.640,1312.2657.11075.54819.13021094807.198

任何帮助表示赞赏。我不喜欢正则表达式。

Answer 1

一种方法是这样做

$result = Get-ChildItem "\\$server\$Path" -Filter "*.log" -File | 
          Select-String -Pattern $text -SimpleMatch |
          Select-Object -ExpandProperty Line |
          ForEach-Object {
              if ($_ -match '([a-z]{3,}\s*\d{2}\s*\d{2}:\d{2}:\d{2}\.\d{3}\s*\d{4}).*GUID ([\d.]+)') {
                  '{0},{1}' -f $matches[1], $matches[2]
              }
          }

$result | Out-File $logfile -Append 

---

解释：

• 我在Select-String cmdlet 中添加了开关-SimpleMatch，因为您似乎想完全匹配$text，而且它在那里不使用正则表达式，这将是最佳选择。
• Select-Object -ExpandProperty Line 可以返回一个匹配行的数组，所以我通过管道将它传递给 ForEach-Object 以循环
• if (..) 使用正则表达式 -match，如果该条件为 $true，我们将执行大括号内的任何操作。
  此外，此测试（如果为 $true）会自动设置一个 $matches 对象数组，我们使用这些匹配项输出一个逗号分隔的行，然后将其收集到变量 $result 中。
• 最后我们简单地将 $result 输出到一个文件中

正则表达式详细信息：

(               Match the regular expression below and capture its match into backreference number 1
   [a-z]        Match a single character in the range between “a” and “z”
      {3,}      Between 3 and unlimited times, as many times as possible, giving back as needed (greedy)
   \s           Match a single character that is a “whitespace character” (spaces, tabs, line breaks, etc.)
      *         Between zero and unlimited times, as many times as possible, giving back as needed (greedy)
   \d           Match a single digit 0..9
      {2}       Exactly 2 times
   \s           Match a single character that is a “whitespace character” (spaces, tabs, line breaks, etc.)
      *         Between zero and unlimited times, as many times as possible, giving back as needed (greedy)
   \d           Match a single digit 0..9
      {2}       Exactly 2 times
   :            Match the character “:” literally
   \d           Match a single digit 0..9
      {2}       Exactly 2 times
   :            Match the character “:” literally
   \d           Match a single digit 0..9
      {2}       Exactly 2 times
   \.           Match the character “.” literally
   \d           Match a single digit 0..9
      {3}       Exactly 3 times
   \s           Match a single character that is a “whitespace character” (spaces, tabs, line breaks, etc.)
      *         Between zero and unlimited times, as many times as possible, giving back as needed (greedy)
   \d           Match a single digit 0..9
      {4}       Exactly 4 times
)
.               Match any single character that is not a line break character
   *            Between zero and unlimited times, as many times as possible, giving back as needed (greedy)
GUID\           Match the characters “GUID ” literally
(               Match the regular expression below and capture its match into backreference number 2
   [\d.]        Match a single character present in the list below
                A single digit 0..9
                The character “.”
      +         Between one and unlimited times, as many times as possible, giving back as needed (greedy)
)