How to delete ONLY same files & folder - powershell

Question

I wanted to update an app.
In order to do this, i want to test if files AND folders from $path_new exists in $path_old. If so, delete those from $path_old and copy those from $path_new, if not, keep them on $path_old.
So, i'll keep everything except updated files.
Edit : Using PowerShell.
Edit : So if an user added a personnal folder in the app mmain folder, he'll keep it.
Maybe i'll look like this :
$FileName = "C:\Share\test.txt"
if (Test-Path $FileName)
{
Remove-Item $FileName
}
But it's not exactly what i want. I think i'll have to add a "for" loop, but how, where ?

Answer 1

This will copy files from the source directory to the target directory. 'Personal files', or files not existant in the source directory, will be ignored while files that exist in both folders are overwritten.
In addition to that, I'd like to point out that your approach to this problem is inefficient so to speak. It's a lot more work to search for files existing in both directories, deleting those, and then copying those over from the new directory to the old directory. Instead you should just use existing file copy actions such as Copy-Item as they have built-in functionality to overwrite existing files.
$target = ".\old"
$source = ".\new"
Get-ChildItem -Path $source | Copy-Item -Destination $target -Recurse -Force -Container
Parameters
-Recurse Copy all files and folders recursively.
-Force Copy items that cannot otherwise be changed, such as copying over a read-only file or alias.
-Container This will retain the folder structure when doing recursive copy actions.