asked on

PowerShell script to compare last write time details in files

Hi,

I am trying to change the Last Write time of some files based on the dates of files in another directory. The files in the other directory have the same name. To do this I am trying to write a PowerShell script that will find the files of a specific date (23 May 2012) in the one directory and then update the last write time of those files with the date from the corresponding files in the other directory.

To change the file date I can just use the below command per file:

$a = Get-Item <FILENAME>; $a.LastWriteTime = $Date

Open in new window

What I am struggling with however is writing a PowerShell script that will find the files of the specific date in one directory and then find the corresponding files in the other directory and then update the dates correctly on the original files. So far I have written this script below to try and prove this can be done but I can’t get it to work. The script should run through and do a check for each file but it is just doing them in one go and not processing them correctly.

$CorrectDatePath="V:\Testing"
$InCorrectDatePath="W:\Testing"

$FilesWithInCorrectDate='Get-ChildItem $InCorrectDatePath -r | Where-Object {$_.lastwritetime -lt "23 May 2012 23:59" -and $_.LastWriteTime -gt "23 May 2012 00:01" } | Select-Object FullName' 

ForEach 
    ($I in $FilesWithInCorrectDate)
    
        {
            Get-ChildItem $CorrectDatePath -r | Select-Object Fullname
            
            if ($FilesWithInCorrectDate = $I)
                {
                    write-host $FilesWithInCorrectDate
                    write-host $I
                    write-host "Filename correct"
                }
            
            else
            
                {
                    write-host $FilesWithInCorrectDate
                    write-host $I
                    Write-host "Filename Incorrect"
                }
        }

Open in new window

This doesn't seem to be processing the files individually and is just spitting them out in one big lump which means it can't check the dates

Meir Rivkin

first of all u have single quote before calling Get-ChildItem which is wrong.
secondly, line 12 is syntax wrong cause u should use -eq when comparing objects.
another thing, u look for files that last write time is between 23 May 2012 23:59 and
23 May 2012 00:01, which always yields nothing, since 23 May 2012 23:59 is greater than 23 May 2012 00:01.
is want the files that the last write time is on 23 May 2012 (whole day) then use this:

$FilesWithInCorrectDate = Get-ChildItem $InCorrectDatePath -r | Where-Object {(Get-Date $files[0].LastWriteTime  -format d) -eq "5/23/2013" } | Select-Object FullName

Open in new window

Meir Rivkin

here's the script, change $newLastWriteTimeDate to valid date.

cls
CorrectDatePath="V:\Testing"
$InCorrectDatePath="W:\Testing"
$newLastWriteTimeDate = "new last write time"
$files = gci $InCorrectDatePath -r | Where-Object {$_.PSIsContainer -eq $false -and (Get-Date $_.LastWriteTime).ToShortDateString() -eq "5/23/2012"} 
$files | %{
	$name = $_.Name
	$file = gci $InCorrectDatePath -r | Where-Object {$_.Name -eq $name }
	$file.LastWriteTime = $Date
}

Open in new window

Qlemo

That's not very efficient. We can use gci with the names directly, which should speed up things. And $Date is not set:

cls
$CorrectDatePath="V:\Testing"
$InCorrectDatePath="W:\Testing"
$newLastWriteTimeDate = "new last write time"
$files = gci $CorrectDatePath -r | Where-Object {$_.PSIsContainer -eq $false -and (Get-Date $_.LastWriteTime).ToShortDateString() -eq "5/23/2012"} 
$files | foreach {
  (gci $InCorrectDatePath -r -include $_.Name).LastWriteTime = $_.LastWriteTime
}

Open in new window

Qlemo

Or this one, which will go thru each directory only once:

cls
$CorrectDatePath="V:\Testing"
$InCorrectDatePath="W:\Testing"
$dt = [DateTime] "05/23/2012"

$files = $null
gci $CorrectDatePath -Recurse |
  ? { !$_.PsIsContainer -and $_.LastWriteTime.Date -eq $dt } |
  % { $files += @{ $_.Name = $_.LastWriteTime } }

gci c:\temp\ee\tst.copy -include $($files.keys) -Recurse |
  ? { $_.LastWriteTime -ne $files[$_.Name] } |
  % { $_.LastWriteTime = $files[$_.Name] }