2013 PowerShell Scripting Games Advanced Event 1 – Parameters Don’t Always Work As Expected

The scenario for this event states the following which has been paraphrased:

Someone allowed log files to build up for around two years and they're starting to causing disk space issues on the server. You need to build a tool to archive the log files because this has happened more than once. Applications write log files to a sub-folder in C:\Application\Log. Examples are C:\Application\Log\App1, C:\Application\Log\OtherApp, and C:\Application\Log\ThisAppAlso. The log files have random file names and a .log extension. After the log files are written to disk, they're no longer used by the applications.

Your tool should archive log files older than 90 days and move them to \\NASServer\Archives, maintaining the source sub-folder stucture such as \\NASServer\Archives\App1.

The source location, destination location, and file age to archive should each be a parameter. Any errors that happen during the move should be clearly displayed. Output should not be displayed if the command completes successfully.

Using Get-ChildItem with the Filter parameter:

I started out working with Get-ChildItem and was almost set on using the Filter parameter to filter the results down to only log files, the problem is that using Filter in that manner would also return any file extension that begins with log such as .log1 as shown in the following results:


So unfortunately if you used the Filter parameter with Get-ChildItem in your solution, it doesn't meets the requirements of this scenario since it will archive more than just .log files.

Using Get-ChildItem with the Include parameter:

The other parameter that I thought would accomplish the task was Get-ChildItem with the Include parameter. The issue I ran into with it is that it only works when using the Recurse parameter. At first, using the Recurse parameter didn't seem to be an issue:


After re-reading the scenario, I decided that I only wanted to move log files in the first level sub-folders and not in the actual C:\Application\Log folder and not in sub-folders deeper than the first level sub-folders so as you can see in the previous image, the Include parameter doesn't accomplish that task.

I ended up using something similar to the following which retrieves only the files in the first level sub-folders that are older than 90 days without using either the Filter or Include parameter:


I'll continue this blog post tomorrow to discuss how I dynamically retrieved this information since the scenario states the folder names could change. I'll discuss how I determined the folder names without making an additional call to the file system. I'll also show you how I used the list of folder names instead of iterating through each file individually to move the files to the correct sub-folder on the destination end.

Update 02/09/14:

The link to my solution is no longer valid so I’m posting it here since I’ve received some requests for it:

 1function Move-LogFile {
 5Move files with a .log extension from the SourcePath to the DestinationPath that are older than Days.
 7Move-LogFile is a function that moves files with a .log extension from the first level subfolders that are specified via
 8the SourcePath parameter to the same subfolder name in the DestinationPath parameter that are older than the number of days
 9specified in the Days parameter. If a subfolder does not exist in the destination with the same name as the source, it will
10be created. This function requires PowerShell version 3.
11.PARAMETER SourcePath
12The parent path of the subfolders where the log files reside. Log files in the actual SourcePath folder will not be archived,
13only first level subfolders of the specified SourcePath location.
14.PARAMETER DestinationPath
15Parent Path of the Destination folder to archive the log files. The name of the original subfolder where the log files reside
16will be created if it doesn't already exist in the Destination folder. Destination subfolders are only created if one or more
17files need to be archived based on the days parameter. Empty subfolders are not created until needed.
19Log files not written to in more than the number of days specified in this parameter are moved to the destination folder location.
21Switch parameter that when specified overwrites destination files if they already exist.
23Move-LogFile -SourcePath 'C:\Application\Log' -DestinationPath '\\NASServer\Archives' -Days 90
25Move-LogFile -SourcePath 'C:\Application\Log' -DestinationPath '\\NASServer\Archives' -Days 90 -Force
28    [CmdletBinding()]
29    param (
30        [string]$SourcePath = 'C:\Application\Log',
31        [string]$DestinationPath = '\\NASServer\Archives',
32        [int]$Days = 90,
33        [switch]$Force
34    )
36    BEGIN {
37        Write-Verbose "Retrieving a list of files to be archived that are older than $($Days) days"
38        try {
39            $files = Get-ChildItem -Path (Join-Path -Path $SourcePath -ChildPath '*\*.log') -ErrorAction Stop |
40                     Where-Object LastWriteTime -lt (Get-Date).AddDays(-$days)
41        }
42        catch {
43            Write-Warning $_.Exception.Message
44        }
46        $folders = $files.directory.name | Select-Object -Unique
47        Write-Verbose "A total of $($files.Count) files have been found in $($folders.Count) folders that require archival"
48    }
50    PROCESS {
51        foreach ($folder in $folders) {
53            $problem = $false
54            $ArchiveDestination = Join-Path -Path $DestinationPath -ChildPath $folder
55            $ArchiveSource = Join-Path -Path $SourcePath -ChildPath $folder
56            $ArchiveFiles = $files | Where-Object directoryname -eq $ArchiveSource
58            if (-not (Test-Path $ArchiveDestination)) {
59                Write-Verbose "Creating a directory named $($folder) in $($DestinationPath)"
60                try {
61                    New-Item -ItemType directory -Path $ArchiveDestination -ErrorAction Stop | Out-Null
62                }
63                catch {
64                    $problem = $true
65                    Write-Warning $_.Exception.Message
66                }
67            }
69            if (-not $problem) {
70                Write-Verbose "Archiving $($ArchiveFiles.Count) files from $($ArchiveSource) to $($ArchiveDestination)"
71                try {
72                    If ($Force) {
73                        $ArchiveFiles | Move-Item -Destination $ArchiveDestination -Force -ErrorAction Stop
74                    }
75                    Else {
76                        $ArchiveFiles | Move-Item -Destination $ArchiveDestination -ErrorAction Stop
77                    }
78                }
79                catch {
80                    Write-Warning $_.Exception.Message
81                }
82            }
84        }
85    }
87    END {
88        Remove-Variable -Name SourcePath, DestinationPath, Days, Force, files, folders, folder,
89        problem, ArchiveDestination, ArchiveSource, ArchiveFiles -ErrorAction SilentlyContinue
90    }