SP validation

$web = Get-SPWeb http://jv-sps15-1

$files = $web.GetFolder("Lib1").Files

$lib2 = $web.Lists["Lib2"]
$lib1 = $web.Lists["Lib1"]

$fld1 = $lib1.Fields["testC"]
$fld2 = $lib2.Fields["testC"]

$validationF = $fld1.ValidationFormula
$validationM = $fld1.ValidationMessage



$fld2.ValidationFormula = ""
$fld2.ValidationMessage = ""
$fld2.Update($true)

$lib2.EnforceDataValidation = $false
$lib2.Update()

foreach($file in $files){
    $file.CopyTo("Lib2/"+$file.Name,$true)
}

$lib2.EnforceDataValidation = $true
$lib2.Update()

$fld2.ValidationFormula = $validationF
$fld2.ValidationMessage = $validationM
$fld2.Update($true)