how to get the last entry in the system object array in powershell

I use the following command to generate a log file in C:\tmp with this naming convention computername_yearmmddhhmm.txt

/xagt.exe -g "C:\tmp\xagt_${env:COMPUTERNAME}_$(Get-Date -Format 'yyyyMMdd_HHmmss').txt"

to read the output of this file using PowerShell I use the code attached below , to obtain the last 20 lines of the logfile I use the below code

$Fireeyefilename = Get-Item  $filename*.txt

Write-Output ("FireEye Connection Status");
Write-Host "-------------------------------------------------------------------------------------------------------"
$foreeyeconnection = Get-Content $Fireeyefilename[$Fireeyefilename.count – 1] -Tail 20 | select-string "m=TCPConnect";
Write-Output ("$($Fireeyefilename[$Fireeyefilename.count – 1])");
Write-Output ("$foreeyeconnection");

as shown above, I save part of the file name in the variable $filename, then I store all the log files created with the naming convention xagt_hostname_* in the variable $Fireeyefilename, and then I read the content of this file using Get-Content.

The problem is that some time the variable ($Fireeyefilename) contains a single log file
like that

PS C:\Program Files (x86)\FireEye\xagt> $Fireeyefilename


    Directory: C:\tmp


Mode                LastWriteTime         Length Name                                                                                                                    
----                -------------         ------ ----                                                                                                                    
-a----       13/07/2023     10:58        8416798 xagt_computername_20230713_105844.txt                                                                                       



PS C:\Program Files (x86)\FireEye\xagt> $Fireeyefilename.GetType()

IsPublic IsSerial Name                                     BaseType                                                                                                      
-------- -------- ----                                     --------                                                                                                      
True     True     FileInfo                                 System.IO.FileSystemInfo                                                                                      

and the $Fireeyefilename variable type becomes System.IO.FileSystemInfo

and some time the $Fireeyefilename variable has multiple log logfiles and the variable type becomes a system array like:

PS C:\Program Files (x86)\FireEye\xagt> $Fireeyefilename.GetType()

IsPublic IsSerial Name                                     BaseType                                                                                                      
-------- -------- ----                                     --------                                                                                                      
True     True     Object[]                                 System.Array                                                                                                  



PS C:\Program Files (x86)\FireEye\xagt> $Fireeyefilename


    Directory: C:\tmp


Mode                LastWriteTime         Length Name                                                                                                                    
----                -------------         ------ ----                                                                                                                    
-a----       13/07/2023     10:58        8416798 xagt_computername_20230713_105844.txt                                                                                       
-a----       13/07/2023     11:03        8428108 xagt_computername_20230713_110307.txt                                                                                       
-a----       13/07/2023     11:03        8428108 xagt_computername_20230713_110337.txt                                                                                       

I need to read the last log file I generated ,in other words thefile with the recent "LastWriteTime"
so I use this code:

Get-Content $Fireeyefilename[$Fireeyefilename.count – 1] -Tail 20 | select-string "m=TCPConnect";

as I mentioned previously, when the variable $Fireeyefilename has a single file name
and its type is system.IO.FileSystemInfo, it will hvave no Count property but the code works
and when the variable $Fireeyefilename type is System.Array, I got the last file using

Get-Content $Fireeyefilename[$Fireeyefilename.count – 1] -Tail 20 | select-string "m=TCPConnect";

Sometimes I couldn't get the last log file I generated using this code:

Get-Content $Fireeyefilename[$Fireeyefilename.count – 1]

so is there a mmethod to get the last log file with the LastWriteTime in he system array variable Last $Fireeyefilename

Take into consideration that I should to generate this file in the C:\tmp location
why there logfiles with the same name, because a lot of users have to generate this file in the same location and is there a suggestion to enhance the code, kindly let me know

You can use the @(...) array subexpression operator to force PowerShell to treat single-item output as an array:

# use @() to ensure `$FireEyeLogFiles` contains an array, 
# regardless of whether there's 0, 1, or multiple files
$FireEyeLogFiles = @(Get-Item $filename*.txt)

# index `-1` will give you the last item in the array
$latestFireEyeLogFile = $FireEyeLogFiles[-1] 
if (-not $latestFireEyeLogFile) {
  Write-Warning "No log files found!"
}
else {
  $latestFireEyeLogFile |Get-Content -Tail 20 |Select-String -Pattern 'm=TCPConnect'
}