powershell 在每个文件中查找并替换具有特定匹配和扩展名的文本

Question

我正在尝试做两件事。首先我要在匹配后删除所有文本，然后用新文本替换匹配行。

在下面的示例中，我想找到行 List of animals 并将所有文档 *.txt 中的所有行替换为 中的文本replaceWithThis.txt.

我下面的第一个 foreach 将删除 动物列表 之后的所有内容，我的第二个 foreach 将替换 动物列表 并因此在该行之后添加新内容replaceWithThis.txt。

replaceWithThis.txt 包含：

List of animals
Cat 5
Lion 3
Bird 2

*.txt 包含：

List of cities
London 2
New York 3
Beijing 6

List of car brands
Volvo 2
BMW 3
Audi 5

List of animals
Cat 1
Dog 3
Bird 7

代码：

$replaceWithThis = Get-Content c:\temp\replaceWithThis.txt -Raw

$allFiles = Get-ChildItem "c:\temp" -recurse | where {$_.extension -eq ".txt"}
$line = Get-Content c:\temp\*.txt | Select-String cLuxPlayer_SaveData | Select-Object -ExpandProperty Line
foreach ($file in $allFiles)
{
    (Get-Content $file.PSPath) |
    ForEach-object { $_.Substring(15,  $_.lastIndexOf('List of animals')) } |
    Set-Content $file.PSPath
}

foreach ($file in $allFiles)
{
    (Get-Content $file.PSPath) |
    Foreach-Object { $_ -replace $line,$replaceWithThis } |
    Set-Content $file.PSPath
}

所有（*.txt）的最终结果应该是：

List of cities
London 2
New York 3
Beijing 6

List of car brands
Volvo 2
BMW 3
Audi 5

List of animals
Cat 5
Lion 3
Bird 2

Answer 1

使用正则表达式，下面的代码应该可以工作：

$filesPath       = 'c:\temp'
$replaceFile     = 'c:\temp\replaceWithThis.txt'
$regexToFind     = '(?sm)(List of animals(?:(?!List).)*)'
$replaceWithThis = (Get-Content -Path $replaceFile -Raw).Trim()

Get-ChildItem -Path $filesPath -Filter *.txt | ForEach-Object {
    $content = $_ | Get-Content -Raw
    if ($content -match $regexToFind) {
        Write-Host "Replacing text in file '$($_.FullName)'"
        $_ | Set-Content -Value ($content -replace $matches[1].Trim(), $replaceWithThis) -Force
    }
}

正则表达式详细信息

(                      Match the regular expression below and capture its match into backreference number 1
   List of animals     Match the characters “List of animals” literally
   (?:                 Match the regular expression below
      (?!              Assert that it is impossible to match the regex below starting at this position (negative lookahead)
         List          Match the characters “List” literally
      )
      .                Match any single character
   )*                  Between zero and unlimited times, as many times as possible, giving back as needed (greedy)
)