如何使用 Powershell 替換文本文件中的多行？

Question

我有一個文件，我可以在文件中獲得 2 行。我有一個包含以下內容的文件。

public class Websites
{
    //private const string URL = "https://au.yahoo.com/?p=us";
    private const string URL = "https://www.google.com/";
    //private const string URL = "https://stackoverflow.com/";
          ....

我可以像這樣單獨獲得 2 行：

$linegoogle = Get-Content "C:\myfile.cs" | Select-String "https://www.google.com/" | Select-Object - 
ExpandProperty Line
$google = $linegoogle.Trim()

$linestackoverflow = Get-Content "C:\myfile.cs" | Select-String "https://stackoverflow.com/" | 
Select-Object -ExpandProperty Line
$stackoverflow = $linestackoverflow.Trim()

但我要做的是以下幾點：

if (condition1)
{
    //replace the 2 lines  with
      
      // private const string URL = "https://www.google.com/";  
     private const string URL = "https://stackoverflow.com/";
}
else if (condition 2)
{
         //replace the 2 lines with

          private const string URL = "https://www.google.com/"; 
         // private const string URL = "https://stackoverflow.com/";
}

Answer 1

當然不是一個優雅的解決方案，但這可能適合你：

# set the condition here. 
# can be either 'stackoverflow', 'google' or 'yahoo' as per your example file.
$condition = 'stackoverflow'

# read the file as single multiline string
$content = Get-Content "C:\myfile.cs" -Raw
# do the replacements depending on what is in $condition
$result  = switch ($condition) {
    'stackoverflow' {
        $content -replace '(?m)^(\s+)(private const string URL = "https://www\.google\.com/.*";)', '$1//$2' -replace
                          '(?m)^(\s+)(private const string URL = "https://au\.yahoo\.com/.*";)', '$1//$2' -replace
                          '(?m)^(\s+)//(private const string URL = "https://stackoverflow\.com/.*";)', '$1$2'
    }
    'google' {
        $content -replace '(?m)^(\s+)(private const string URL = "https://stackoverflow\.com/.*";)', '$1//$2' -replace
                          '(?m)^(\s+)(private const string URL = "https://au\.yahoo\.com/.*";)', '$1//$2' -replace
                          '(?m)^(\s+)//(private const string URL = "https://www\.google\.com/.*";)', '$1$2'
    }
    'yahoo' {
        $content -replace '(?m)^(\s+)(private const string URL = "https://stackoverflow\.com/.*";)', '$1//$2' -replace
                          '(?m)^(\s+)(private const string URL = "https://www\.google\.com/*";)', '$1//$2' -replace
                          '(?m)^(\s+)//(private const string URL = "https://au\.yahoo\.com/.*";)', '$1$2'
    }
}

# show the result on screen
$result

# write back to file
$result | Set-Content -Path "C:\myfile.cs"

請記住， -replace使用正則表達式，因此您需要使用反斜杠對 url 中的特殊字符（在這種情況下，只有點）進行轉義。 還要在 url 中的最后一個斜杠后面附加.*以說明任何可能的查詢字符串。