Alert if file missing using Powershell

The following Powershell script can be used to send an email alert when a file is missing from a folder or it is the same file from a previous check:

$path_mask = "yourfile_*.txt"

$previous_file_store = "lastfileread.txt"

$script_name = "File Check"

###### Functions ##########

Function EMailLog($subject, $message)

{

   $emailTo = "juanito@yourserver.com"

   $emailFrom = "alert@yourserver.com"

   $smtpserver="smtp.yourserver.com"   

   $smtp=new-object Net.Mail.SmtpClient($smtpServer)

   $smtp.Send($emailFrom, $emailTo, $subject, $message)

}

Try

{

   #get files that match the mask

   $curr_file = dir $path_mask |  select name

   if ($curr_file.count -gt 0)

   {

       #file found

       #check if the file is different from the previous file read

       $previous_file = Get-Content $previous_file_store

       $curr_file_name = $curr_file.Item(0).Name

       if ($previous_file.trim() -eq  $curr_file_name.trim())

       {

           $msg = "Found same file as previous check: $previous_file and $curr_file_name"

           $msg

           EMailLog "$script_name Error" $msg

       }

       else

       {

           #different file, record its name for comparing in the next run

           $curr_file.Item(0).Name | out-file -filepath $previous_file_store

       }

   }

   else

   {

       $msg = "$path_mask Not found"

       $msg

       EMailLog "$script_name Error" $msg

   }

}

Catch [system.exception]

{

   "Caught a system exception "

   $error

   $error.Exception | EMailLog  "$script_name System error" $_

   

}