write-output "" | out-file -filepath c:inventory.txt

Add-PSSnapin Microsoft.Sharepoint.Powershell

[Microsoft.SharePoint.SPSecurity]::RunWithElevatedPrivileges(
{
    $siteCollectionURL = "http://srvr1.company.com/sites/TestRC/"
    $siteColl = Get-SPSite $siteCollectionURL
    $doclibs = @("CB")
    $subFolder = @("folder1" , "folder2" ,"folder3" )
    Function GetFiles($Folder)
    {
        Write-Host "+"$Folder.Name

        #Loop through all subfolders and call the function recursively
        foreach ($subFolder in $Folder.SubFolders)
        {
            if(($subFolder.Name -eq "Public") -Or ($subFolder.Name -eq "folder1") -Or ($subFolder.Name -eq "folder2" ))
            {
                Write-Host "`t" -NoNewline
                $Files = $subFolder. | where {$_.FileSystemObjectType -eq "File"} # here i am getting null value though items exist
                if($Files -eq $null)
                {
                   Write-Host "+++++ There is no file in this subfolder " + $subFolder.Title
                   Write-Output "+++++ There is no file in this subfolder " +  $subFolder.Title | out-file -filepath c:inventory.txt -append
                }
                else
                {
                    foreach ($file in $Files)
                    {
                        $itemFile = $file.File
                        if( $itemFile.CheckOutStatus -ne "None" )
                        {
                            $itemFile.CheckIn("Automatic CheckIn.(Administrator)")
                        }

                        Write-Host "+++++ Deleting file " $file.Name
                        Write-Output "+++++ Deleting file " $file.Name | out-file -filepath c:inventory.txt -append
                        $file.Delete()
                        Write-Host "+++++ Done with Deleting file " $file.Name
                        Write-Output "+++++ Done with Deleting file " $file.Name | out-file -filepath c:inventory.txt -append
                    }
                }
                GetFiles($Subfolder)
            }
        }
    }
    if($siteColl -ne $null)
    {
        Write-Host "+ Site Collection : " $siteColl.Name
        Write-Output "+ Site Collection : " $siteColl.Name | out-file -filepath c:inventory.txt -append
        Write-Host "++ Site Collection : " $siteColl.Url
        foreach($subWeb in $siteColl.AllWebs)
        {
            if($subWeb -ne $null)
            {
                #Print each Subsite
                Write-Host "+++ Sub Web : " $subWeb.Url
                Write-Output "+++ Sub Web : " $subWeb.Url | out-file -filepath c:inventory.txt -append

                # $Libraries = $subWeb.Lists | where {$_.BaseType -eq "DocumentLibrary"}
                foreach ($doclib in $doclibs)
                {
                    $library =  $subWeb.Lists[$doclib]
                    Write-Host "++++ Getng files from library : " $library.Title
                    Write-Output "++++ Getting files from library : " $library.Title | out-file -filepath c:inventory.txt -append
                    #$Files = $library.Items | where {$_.FileSystemObjectType -eq "File"}
                    GetFiles($library.RootFolder)
                }
            }
            # Write-host -ForegroundColor Red ("Items to be deleted : " + $subWeb.RecycleBin.Count.toString())
            # Write-Output ("Items to be deleted : " +$subWeb.RecycleBin.Count.toString()) | out-file -filepath c:inventory.txt -append
            # $now = Get-Date
            # Write-host -ForegroundColor Red ("Deleting started at " + $now.toString())
            # Write-Output ("Deleting started at " +$now.toString()) | out-file -filepath c:inventory.txt -append
            # if ($subWeb.RecycleBin.Count -ne $null)
            # {
            #    $subWeb.RecycleBin.DeleteAll();
            # }
            # $now = Get-Date
            # write-host -ForegroundColor Red ("Deleting completed at " +$now.toString())
            # Write-Output ("Deleting completed at " +$now.toString()) | out-file -filepath c:inventory.txt -append
            $subWeb.Dispose()
        }
        else
        {
            Echo $subWeb  "does not exist"
        }
    }
    # write-host $siteColl
    # write-host -ForegroundColor Red ("Items to be deleted : " +$siteColl.RecycleBin.Count.toString())
    # Write-Output ("Items to be deleted : " +$siteColl.RecycleBin.Count.toString()) | out-file -filepath c:inventory.txt -append
    # $now = Get-Date
    # write-host -ForegroundColor Red ("Deleting started at " +$now.toString())
    # Write-Output ("Deleting started at " +$now.toString()) | out-file -filepath c:inventory.txt -append
    # if ($siteColl.RecycleBin.Count -ne 0) {
    #   $siteColl.RecycleBin.DeleteAll();
    # }
});