Powershell if changed Set-Content

Question

I have a PowerShell script that I use to change text in a number of files. The following script will work & changes the text as expected.

Get-ChildItem $FileFolder -Recurse |
select -ExpandProperty fullname |
foreach {
     (Get-Content $_) |
     ForEach-Object {$_ -replace $old $new } |
         Set-Content $_
     }

The problem is though, it changes every file that it opens, so everything has a timestamp of when the job was run even if nothing was changed.

I have tried something similar to what is here but it gives me an error:

The term 'if' is not recognized as the name of a cmdlet, function, etc...

Here is the code I am trying to run:

Get-ChildItem $FileFolder -Recurse |
select -ExpandProperty fullname |
foreach {
    $b = ($a = Get-Content $_) |
    ForEach-Object {$_ -replace $old $new } |
       if (Compare $a $b -PassThru) {
           $b | Set-Content $_
          }
    }

I know that the code isn't right, but if I move it inside the ForEach-Object , it won't run either.

What I want to do is to use the Set-Content statement only if the contents of the file have changed. Would appreciate any thoughts as to how best to do this.

Answer 1

What you can do is look for the string before getting and setting content. Something like:

Get-ChildItem $FileFolder -Recurse |
select -ExpandProperty fullname |
foreach {
     If(Select-String -Path $_ -SimpleMatch $old -quiet){
          (Get-Content $_) |
          ForEach-Object {$_ -replace $old $new } |
              Set-Content $_
          }
     }