PowerShell Log File Monitoring – AD Migration

A lot of log files need to be analyzed during an Active Directory migration.

In case there is a log, you mostly have to write an email, update a database or do something like that.

This is a simple example of a PowerShell log file monitoring script for a share:

PowerShell: Log file Supervision for Share

The code checks every 10 sec if there is a new logfile in $share (“\\server\share\”) which starts with $startsWith (“ADMT*”).
The asterisk is a wild-card and stands for any sequence of characters.

$share = “\\server\share\” # Change to your share
$startsWith = “ADMT*”
$logs = Get-ChildItem ($share + $startsWith) | Sort-Object LastWriteTime -Descending # Get all files starting with $startsWith in $share and sort by DateModified. Latest is first.
$lastWriteTime = $logs[0].LastWriteTime # The time stamp of the latest log file
 
while($true) {
       $logs = Get-ChildItem ($share + $startsWith) | Where-Object {($_.LastWriteTime -gt $lastWriteTime)} # Get all files starting with $startsWith in $share that are newer than $lastWriteTime
       if($logs -ne $null) { # If we have new logs…
             $logs = $logs | Sort-Object LastWriteTime -Descending # Sort logs descending
             if($logs.Count -eq $null) { # If we have one log…
                    $lastWriteTime = $logs.LastWriteTime # Set $lastWriteTime to DateModified of new log
             }
             else {
                    $lastWriteTime = $logs[0].LastWriteTime # Otherwise, use DateModified of latest log
             }
             foreach($logFile in $logs) { # for each log file found do…
                    # <YOUR CODE HERE>
             }
       }
       else { # If there are no new logs
             Write-Host “no new logs found. Sleeping for 10s”
       }
       Sleep 10 # Sleep for 10s
}