PowerShell Script to Find and Replace for all Files with a Specific Extension

Question

Here a first attempt at the top of my head.

$configFiles = Get-ChildItem . *.config -rec
foreach ($file in $configFiles)
{
    (Get-Content $file.PSPath) |
    Foreach-Object { $_ -replace "Dev", "Demo" } |
    Set-Content $file.PSPath
}

PowerShell is a good choice ;) It is very easy to enumerate files in given directory, read them and process.

The script could look like this:

Get-ChildItem C:\Projects *.config -recurse |
    Foreach-Object {
        $c = ($_ | Get-Content) 
        $c = $c -replace '<add key="Environment" value="Dev"/>','<add key="Environment" value="Demo"/>'
        [IO.File]::WriteAllText($_.FullName, ($c -join "`r`n"))
    }

I split the code to more lines to be readable for you. Note that you could use Set-Content instead of [IO.File]::WriteAllText, but it adds new line at the end. With WriteAllText you can avoid it.

Otherwise the code could look like this: $c | Set-Content $_.FullName.

This approach works well:

gci C:\Projects *.config -recurse | ForEach {
  (Get-Content $_ | ForEach {$_ -replace "old", "new"}) | Set-Content $_ 
}

• Change "old" and "new" to their corresponding values (or use variables).
• Don't forget the parenthesis -- without which you will receive an access error.

I would go with xml and xpath:

dir C:\Projects\project_*\project*.config -recurse | foreach-object{  
   $wc = [xml](Get-Content $_.fullname)
   $wc.SelectNodes("//add[@key='Environment'][@value='Dev']") | Foreach-Object {$_.value = 'Demo'}  
   $wc.Save($_.fullname)  
}

This powershell example looks for all instances of the string "\foo\" in a folder and its subfolders, replaces "\foo\" with "\bar\" AND DOES NOT REWRITE files that don't contain the string "\foo\" This way you don't destroy the file last update datetime stamps where the string was not found:

Get-ChildItem  -Path C:\YOUR_ROOT_PATH\*.* -recurse 
 | ForEach {If (Get-Content $_.FullName | Select-String -Pattern '\\foo\\') 
           {(Get-Content $_ | ForEach {$_ -replace '\\foo\\', '\bar\'}) | Set-Content $_ }
           }