How can I replace every occurrence of a String in

Question

Using PowerShell, I want to replace all exact occurrences of [MYID] in a given file with MyValue. What is the easiest way to do so?

Answer 1

Small correction for the Set-Content command. If the searched string is not found the Set-Content command will blank (empty) the target file.

You can first verify if the string you are looking for exist or not. If not it will not replace anything.

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"}

Answer 2

After searching too much I figure out the simplest line to do this without changing the encoding is:

Get-Content path/to/file.ext | out-file -encoding ASCII targetFile.ext

Answer 3

This is what I use, but it is slow on large text files.

get-content $pathToFile | % { $_ -replace $stringToReplace, $replaceWith } | set-content $pathToFile

If you are going to be replacing strings in large text files and speed is a concern, look into using System.IO.StreamReader and System.IO.StreamWriter.

try
{
   $reader = [System.IO.StreamReader] $pathToFile
   $data = $reader.ReadToEnd()
   $reader.close()
}
finally
{
   if ($reader -ne $null)
   {
       $reader.dispose()
   }
}

$data = $data -replace $stringToReplace, $replaceWith

try
{
   $writer = [System.IO.StreamWriter] $pathToFile
   $writer.write($data)
   $writer.close()
}
finally
{
   if ($writer -ne $null)
   {
       $writer.dispose()
   }
}

(The code above has not been tested.)

There is probably a more elegant way to use StreamReader and StreamWriter for replacing text in a document, but that should give you a good starting point.

Answer 4

A bit old and different, as I needed to change a certain line in all instances of a particular file name.

Also, Set-Content was not returning consistent results, so I had to resort to Out-File.

Code below:

---

$FileName =''
$OldLine = ''
$NewLine = ''
$Drives = Get-PSDrive -PSProvider FileSystem
foreach ($Drive in $Drives) {
    Push-Location $Drive.Root
        Get-ChildItem -Filter "$FileName" -Recurse | ForEach { 
            (Get-Content $_.FullName).Replace($OldLine, $NewLine) | Out-File $_.FullName
        }
    Pop-Location
}

---

This is what worked best for me on this PowerShell version:

Major.Minor.Build.Revision

5.1.16299.98

Answer 5

This worked for me using the current working directory in PowerShell. You need to use the FullName property, or it won't work in PowerShell version 5. I needed to change the target .NET framework version in ALL my CSPROJ files.

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