Get last access date/time for all SharePoint site collections with Powershell

This script gets list of all administrators and last access date/time for each SharePoint site collection.
The script saves output in tab separated format (.csv) file. 


Save code as .ps1 file and start in Windows PowerShell

#Set file location for saving information. We'll create a tab separated file.
$FileLocation = "C:\Temp\Report.csv"


#Load SharePoint snap-in
Add-PSSnapin Microsoft.SharePoint.PowerShell

#Add color
function Receive-Color
{
    process { Write-Host $_ -ForegroundColor Green }
}

#Fetches webapplications in the farm
$WebApplications = Get-SPWebApplication -IncludeCentralAdministration
Write-Output "URL `t Site Collection Owner `t Site Collection Secondary Owner `t Site Collection Admin `t Last Access date `t ContentModified" | Out-file $FileLocation

foreach($WebApplication in $WebApplications){
    #Fetches site collections list within sharepoint webapplication
    Write-Output ""
    Write-Output "Working on web application $($WebApplication.Url)" | Receive-Color
    $Sites = Get-SPSite -WebApplication $WebApplication -Limit All
    foreach($Site in $Sites)
    {   
    $Admins=""
   #Get all Site Collection Administrators
      foreach ($siteCollAdmin in $Site.RootWeb.SiteAdministrators)
      {
        $Admins+= $siteCollAdmin.LoginName +";"
      }
      foreach($web in $Site.Allwebs)
      {
      $Lastaccessed = $web.LastItemModifiedDate
      $ContentModified = $Site.LastContentModifiedDate
    
      }
    
            #Fetches information for each  site
            Write-Output "$($Site.Url) `t $($Site.Owner.Name) `t $($Site.SecondaryContact.Name) `t $($Admins) `t $($Lastaccessed) `t $($ContentModified)" | Out-File $FileLocation -Append
            $Site.Dispose()
    }
}

#Unload SharePoint snap-in
Remove-PSSnapin Microsoft.SharePoint.PowerShell

Write-Output ""
Write-Output "Script Execution finished" | Receive-Color

 Ref: http://panky-sharma.blogspot.com/2016/08/last-access-date-and-time-for.html