[powershell] Finding modified date of a file/folder

I am very new to PowerShell, and I was hoping I could get some help creating a script that tells me the modified date of a file.

I wish I knew more about PowerShell, as I feel like I am asking a lot (all my free-time this week will be dedicated to learning PowerShell better). Pointing me in the direction of where to learn how to do this would be very helpful as well.

Here is the complete rundown. I need to run a report daily that checks a list of computers at 90 different stores to make sure their a certain backup was performed. The modified date should tell if the backup had been performed, and will be set to the previous date.

If the modified date is yesterday, then there does not need to be an output. If it is not yesterday, I would like to have the output in the PowerShell window, or to a text file, whichever would be easier.

I also have to check that a folder is no older than seven days for each of the 90 stores, with the same criteria for the output. The idea that I have would be like this for each store

For Store 1:

Check file date for \\server\store\computer\c:\folder\"newest modified date in folder"
if date equals yesterday
   then do nothing
if date does not equal yesterday
   then output "Test did not backup"

check folder modified date for \\server\sample\store\backupfolder
if date equals <7 days old
   then do nothign
if date equals >7 days old
   then output "test did not backup"

Sorry for not proving my research effort, I am very new to Powershell and I was on a deadline to get this done. I have, since yesterday, learned how to do everything that I needed to do with this script. Thanks to @Keith for setting me on the correct path. I ended up using the following code to accomplish my goal of only out-putting the location where result was false.

$a = Get-ChildItem \\server\XXX\Received_Orders\*.* | Where{$_.LastWriteTime -ge (Get-Date).AddDays(-7)}
if ($a = (Get-ChildItem \\server\XXX\Received_Orders\*.* | Where{$_.LastWriteTime -ge (Get-Date).AddDays(-7)}))
{
}
Else
{
    'STORE XXX HAS NOT RECEIVED ANY ORDERS IN THE PAST 7 DAYS'
}


$b = Get-ChildItem \\COMP NAME\Folder\*.* | Where{$_.LastWriteTime -ge (Get-Date).AddDays(-1)}
if ($b = (Get-ChildItem \\COMP NAME\TFolder\*.* | Where{$_.LastWriteTime -ge (Get-Date).AddDays(-1)}))
{
}
Else
{
    'STORE XXX DID NOT RUN ITS BACKUP LAST NIGHT'
}

You can try dirTimesJS.bat and fileTimesJS.bat

example:

C:\>dirTimesJS.bat %windir%

directory timestamps for C:\Windows :

Modified : 2020-11-22 22:12:55
Modified - milliseconds passed : 1604607175000
Modified day of the week : 4

Created : 2019-12-11 11:03:44
Created - milliseconds passed : 1575709424000
Created day of the week : 6

Accessed : 2020-11-16 16:39:22
Accessed - milliseconds passed : 1605019162000
Accessed day of the week : 2

C:\>fileTimesJS.bat %windir%\notepad.exe

file timestamps for C:\Windows\notepad.exe :

Modified : 2020-09-08 08:33:31
Modified - milliseconds passed : 1599629611000
Modified day of the week : 3

Created : 2020-09-08 08:33:31
Created - milliseconds passed : 1599629611000
Created day of the week : 3

Accessed : 2020-11-23 23:59:22
Accessed - milliseconds passed : 1604613562000
Accessed day of the week : 4

Here's what worked for me:

$a = Get-ChildItem \\server\XXX\Received_Orders\*.* | Where{$_.LastWriteTime -ge (Get-Date).AddDays(-7)}
if ($a = (Get-ChildItem \\server\XXX\Received_Orders\*.* | Where{$_.LastWriteTime -gt (Get-Date).AddDays(-7)}  
#Im using the -gt switch instead of -ge
{}
Else
{
'STORE XXX HAS NOT RECEIVED ANY ORDERS IN THE PAST 7 DAYS'
}


$b = Get-ChildItem \\COMP NAME\Folder\*.* | Where{$_.LastWriteTime -ge (Get-Date).AddDays(-1)}
if ($b = (Get-ChildItem \\COMP NAME\TFolder\*.* | Where{$_.LastWriteTime -gt (Get-Date).AddDays(-1)))}
{}
Else
{
'STORE XXX DID NOT RUN ITS BACKUP LAST NIGHT'
}

To get the modified date on a single file try:

$lastModifiedDate = (Get-Item "C:\foo.tmp").LastWriteTime

To compare with another:

$dateA= $lastModifiedDate 
$dateB= (Get-Item "C:\other.tmp").LastWriteTime

if ($dateA -ge $dateB) {
  Write-Host("C:\foo.tmp was modified at the same time or after C:\other.tmp")
} else {
  Write-Host("C:\foo.tmp was modified before C:\other.tmp")
}

PowerShell code to find all document library files modified from last 2 days.

$web = Get-SPWeb -Identity http://siteName:9090/ 
        $list = $web.GetList("http://siteName:9090/Style Library/")
        $folderquery =  New-Object Microsoft.SharePoint.SPQuery  
        $foldercamlQuery =  
        '<Where>   <Eq> 
                <FieldRef Name="ContentType" />  <Value Type="text">Folder</Value> 
            </Eq> </Where>' 
        $folderquery.Query = $foldercamlQuery 
        $folders = $list.GetItems($folderquery) 
        foreach($folderItem in $folders) 
        { 
            $folder = $folderItem.Folder
            if($folder.ItemCount -gt 0){ 
            Write-Host " find Item count " $folder.ItemCount
                $oldest = $null
                $files = $folder.Files

                $date = (Get-Date).AddDays(-2).ToString(“MM/dd/yyyy”)
                foreach ($file in $files){ 
                    if($file.Item["Modified"]-Ge $date)
                    {
                        Write-Host "Last 2 days modified folder name:"   $folder   " File Name: "  $file.Item["Name"]   " Date of midified: "  $file.Item["Modified"] 
                    } 
                } 
            } 
            else
             { 
                Write-Warning "$folder['Name'] is empty" 
            } 
        }