$filePath = "C:\Users\CM\Desktop\testfile.txt"
$dateTime = Get-Date
Write-Host "Script started at" $dateTime

while(1)
{
    $dateTime = Get-Date 
    $dateTime = $dateTime -replace "`t|`n|`r",""
    $dateTime = $dateTime -replace " ;|; ",";"

    Write-Output $dateTime | Out-File -FilePath $filePath -Append
    Start-Sleep -s 1
}