(Get-Content file.txt) | 
Foreach-Object {$_ -replace '\[MYID\]','MyValue'}  | 
Out-File file.txt

注意(Get-Content file.txt)周围的括号是必需的:

Without the parenthesis the content is read, one line at a time, and flows down the pipeline until it reaches out-file or set-content, which tries to write to the same file, but it's already open by get-content and you get an error. The parenthesis causes the operation of content reading to be performed once (open, read and close). Only then when all lines have been read, they are piped one at a time and when they reach the last command in the pipeline they can be written to the file. It's the same as $content=content; $content | where ...

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)"}

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

如果需要替换多个文件中的字符串:

值得注意的是，这里发布的不同方法在完成所需时间方面可能有很大不同。对我来说，我经常有大量的小文件。为了测试哪个性能最好，我在40,693个单独的文件中提取了5.52 GB(5,933,604,999字节)的XML，并运行了我在这里找到的三个答案:

## 5.52 GB (5,933,604,999 bytes) of XML files (40,693 files) 
$xmls = (Get-ChildItem -Path "I:\TestseT\All_XML" -Recurse -Filter *.xml).FullName

#### Test 1 - Plain Replace
$start = Get-Date
foreach ($xml in $xmls) {
    (Get-Content $xml).replace("'", " ") | Set-Content $xml
}
$end = Get-Date
New-TimeSpan –Start $Start –End $End
# TotalMinutes: 103.725113128333

#### Test 2 - Replace with -Raw
$start = Get-Date
foreach ($xml in $xmls) {
    (Get-Content $xml -Raw).replace("'", " ") | Set-Content $xml
}
$end = Get-Date
New-TimeSpan –Start $Start –End $End
# TotalMinutes: 10.1600227983333

#### Test 3 - .NET, System.IO
$start = Get-Date
foreach ($xml in $xmls) {
    $txt = [System.IO.File]::ReadAllText("$xml").Replace("'"," ") 
    [System.IO.File]::WriteAllText("$xml", $txt)
}
$end = Get-Date
New-TimeSpan –Start $Start –End $End
# TotalMinutes: 5.83619516833333

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

我更喜欢使用。net的file类和它的静态方法，如下面的例子所示。

$content = [System.IO.File]::ReadAllText("c:\bla.txt").Replace("[MYID]","MyValue")
[System.IO.File]::WriteAllText("c:\bla.txt", $content)

这样做的优点是使用单个String，而不是像Get-Content那样使用String数组。这些方法还负责文件的编码(UTF-8 BOM等)，而不需要您在大多数时候负责。

此外，与使用Get-Content和管道连接到Set-Content的算法相比，这些方法不会弄乱行结束符(可能会使用Unix行结束符)。

所以对我来说:几年下来会坏掉的东西更少。

在使用. net类时，一个鲜为人知的事情是，当您键入“[System.IO.”在PowerShell窗口中，您可以按Tab键来步进那里的方法。