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I have many files with different names per day. How can I filter them by the date in their name?

For example:


And my code snippet:

$RetainedDays = 7
$FileNameRegex = "\w+_(\d+)\.\w+"
$ArchiveBoundary = $(Get-Date -Format yyyyMMdd) - $RetainedDays
$ProcessFiles = Get-ChildItem -Path $RootPath -Recurse |
    Where-Object { $_.Name -match $FileNameRegex }

I have regex filter for it : \w+_(\d+)\.\w+, that gives me back the date in $Matches variable, but how can I combine them, and get back the file list, with those files, which older than 7 days?

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I think questions like this are better for stackoverflow then serverfault. – tony roth May 9 '13 at 15:28
It's possible, but I doesn't know, how can I move the question into stackoverflow. Otherwise it's not a programming question. PowerShell is a script language, what is useful to system administrators, like me and possibly for you. – gazsiazasz May 9 '13 at 19:52

See if this helps get you closer to what you're trying to do.

$RootPath = "C:\temp"
$ProcessFiles = @()
$RetainedDays = 7
$Today = get-date -format yyyyMMdd
$FileNameRegex  = "\w+_(\d+)\.\w+"
foreach ($File in Get-ChildItem -Path $RootPath) {
   $match = [regex]::matches($File, $FileNameRegex )
   $FileNameDate = $match[0].Groups[1].Value
   if (($Today - $FileNameDate) -ge $RetainedDays) { $ProcessFiles += $File }
share|improve this answer
And I agree with Tony, stackoverflow would be the better choice. – Bruce May 9 '13 at 20:29

It's not too nice, but works! :)

$RetainedDays = 14

$ArchiveBoundary = (Get-Date).AddDays(-$RetainedDays).ToString('yyyyMMdd')

$ProcessFiles = Get-ChildItem -Path $RootPath -Recurse |
    Where-Object { ($_.BaseName -split '_|\.')[1] -lt $ArchiveBoundary }
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