下面是一个相当简单的例子，它支持多行正则表达式、多个文件(使用管道)、指定输出编码等。由于ReadAllText方法，不建议用于非常大的文件。

# Update-FileText.ps1

#requires -version 2

<#
.SYNOPSIS
Updates text in files using a regular expression.

.DESCRIPTION
Updates text in files using a regular expression.

.PARAMETER Pattern
Specifies the regular expression pattern.

.PARAMETER Replacement
Specifies the regular expression replacement pattern.

.PARAMETER Path
Specifies the path to one or more files. Wildcards are not supported. Each file is read entirely into memory to support multi-line searching and replacing, so performance may be slow for large files.

.PARAMETER CaseSensitive
Specifies case-sensitive matching. The default is to ignore case.

.PARAMETER SimpleMatch
Specifies a simple match rather than a regular expression match (i.e., the Pattern parameter specifies a simple string rather than a regular expression).

.PARAMETER Multiline
Changes the meaning of ^ and $ so they match at the beginning and end, respectively, of any line, and not just the beginning and end of the entire file. The default is that ^ and $, respectively, match the beginning and end of the entire file.

.PARAMETER UnixText
Causes $ to match only linefeed (\n) characters. By default, $ matches carriage return+linefeed (\r\n). (Windows-based text files usually use \r\n as line terminators, while Unix-based text files usually use only \n.)

.PARAMETER Overwrite
Overwrites a file by creating a temporary file containing all replacements and then replacing the original file with the temporary file. The default is to output but not overwrite.

.PARAMETER Force
Allows overwriting of read-only files. Note that this parameter cannot override security restrictions.

.PARAMETER Encoding
Specifies the encoding for the file when -Overwrite is used. Possible values for this parameter are ASCII, BigEndianUnicode, Unicode, UTF32, UTF7, and UTF8. The default value is ASCII.

.INPUTS
System.IO.FileInfo.

.OUTPUTS
System.String (single-line file) or System.String[] (file with more than one line) without the -Overwrite parameter, or nothing with the -Overwrite parameter.

.LINK
about_Regular_Expressions

.EXAMPLE
C:\> Update-FileText.ps1 '(Ferb) and (Phineas)' '$2 and $1' Story.txt

This command replaces the text 'Ferb and Phineas' with the text 'Phineas and Ferb' in the file Story.txt and outputs the content. Note that the pattern and replacement strings are enclosed in single quotes to prevent variable expansion.

.EXAMPLE
C:\> Update-FileText.ps1 'Perry' 'Agent P' Story2.txt -Overwrite

This command replaces the text 'Perry' with the text 'Agent P' in the file Story2.txt.
#>

[CmdletBinding(SupportsShouldProcess = $true,ConfirmImpact = "High")]
param(
  [Parameter(Mandatory = $true,Position = 0,ValueFromPipeline = $true)]
  [String[]] $Path,

  [Parameter(Mandatory = $true,Position = 1)]
  [String] $Pattern,

  [Parameter(Mandatory = $true,Position = 2)]
  [AllowEmptyString()]
  [String] $Replacement,

  [Switch] $CaseSensitive,

  [Switch] $SimpleMatch,

  [Switch] $Multiline,

  [Switch] $UnixText,

  [Switch] $Overwrite,

  [Switch] $Force,

  [ValidateSet("ASCII","BigEndianUnicode","Unicode","UTF32","UTF7","UTF8")]
  [String] $Encoding = "ASCII"
)

begin {
  function Get-TempName {
    param(
      $path
    )
    do {
      $tempName = Join-Path $path ([IO.Path]::GetRandomFilename())
    }
    while ( Test-Path $tempName )
    $tempName
  }

  if ( $SimpleMatch ) {
      $Pattern = [Regex]::Escape($Pattern)
  }
  else {
    if ( -not $UnixText ) {
      $Pattern = $Pattern -replace '(?<!\\)\$','\r$'
    }
  }

  function New-Regex {
    $regexOpts = [Text.RegularExpressions.RegexOptions]::None
    if ( -not $CaseSensitive ) {
      $regexOpts = $regexOpts -bor [Text.RegularExpressions.RegexOptions]::IgnoreCase
    }
    if ( $Multiline ) {
      $regexOpts = $regexOpts -bor [Text.RegularExpressions.RegexOptions]::Multiline
    }
    New-Object Text.RegularExpressions.Regex $Pattern,$regexOpts
  }

  $Regex = New-Regex

  function Update-FileText {
    param(
      $path
    )
    $pathInfo = Resolve-Path -LiteralPath $path
    if ( $pathInfo ) {
      if ( (Get-Item $pathInfo).GetType().FullName -eq "System.IO.FileInfo" ) {
        $fullName = $pathInfo.Path
        Write-Verbose "Reading '$fullName'"
        $text = [IO.File]::ReadAllText($fullName)
        Write-Verbose "Finished reading '$fullName'"
        if ( -not $Overwrite ) {
          $regex.Replace($text,$Replacement)
        }
        else {
          $tempName = Get-TempName (Split-Path $fullName -Parent)
          Set-Content $tempName $null -Confirm:$false
          if ( $? ) {
            Write-Verbose "Created file '$tempName'"
            try {
              Write-Verbose "Started writing '$tempName'"
              [IO.File]::WriteAllText("$tempName",$Regex.Replace($text,$Replacement),[Text.Encoding]::$Encoding)
              Write-Verbose "Finished writing '$tempName'"
              Write-Verbose "Started copying '$tempName' to '$fullName'"
              Copy-Item $tempName $fullName -Force:$Force -ErrorAction Continue
              if ( $? ) {
                Write-Verbose "Finished copying '$tempName' to '$fullName'"
              }
              Remove-Item $tempName
              if ( $? ) {
                Write-Verbose "Removed file '$tempName'"
              }
            }
            catch [Management.Automation.MethodInvocationException] {
              Write-Error $Error[0]
            }
          }
        }
      }
      else {
        Write-Error "The item '$path' must be a file in the file system." -Category InvalidType
      }
    }
  }
}

process {
  foreach ( $PathItem in $Path ) {
    if ( $Overwrite ) {
      if ( $PSCmdlet.ShouldProcess("'$PathItem'","Overwrite file") ) {
        Update-FileText $PathItem
      }
    }
    else {
      Update-FileText $PathItem
    }
  }
}

在Github上也可以找到。

用途(V3版本):

(Get-Content c:\temp\test.txt).replace('[MYID]', 'MyValue') | Set-Content c:\temp\test.txt

对于V2:

(Get-Content c:\temp\test.txt) -replace '\[MYID\]', 'MyValue' | Set-Content c:\temp\test.txt

上面的只对“一个文件”运行，但你也可以对文件夹中的多个文件运行:

Get-ChildItem 'C:yourfile*.xml' -Recurse | ForEach {
     (Get-Content $_ | ForEach  { $_ -replace '[MYID]', 'MyValue' }) |
     Set-Content $_
}

对Set-Content命令的小修正。如果没有找到搜索的字符串，Set-Content命令将清空目标文件。

您可以首先验证要查找的字符串是否存在。否则，它将无法取代任何东西。

If (select-string -path "c:\Windows\System32\drivers\etc\hosts" -pattern "String to look for") `
    {(Get-Content c:\Windows\System32\drivers\etc\hosts).replace('String to look for', 'String to replace with') | Set-Content c:\Windows\System32\drivers\etc\hosts}
    Else{"Nothing happened"}

你可以尝试这样做:

$path = "C:\testFile.txt"
$word = "searchword"
$replacement = "ReplacementText"
$text = get-content $path 
$newText = $text -replace $word,$replacement
$newText > $path

使用PowerShell中的当前工作目录，这对我来说很有效。您需要使用FullName属性，否则它将在PowerShell版本5中不起作用。我需要在所有CSPROJ文件中更改目标. net框架版本。

gci -Recurse -Filter *.csproj |
% { (get-content "$($_.FullName)")
.Replace('<TargetFramework>net47</TargetFramework>', '<TargetFramework>net462</TargetFramework>') |
 Set-Content "$($_.FullName)"}