open(FG,"$ARGV[0]") || die &writelog(1,"INFO: processfile_rt: Unable to open log file: $!");
my $str = <FG>;
   while($str =~ /Message dump:((?:(?!Message dump:).)*)/gs)
   {
       print "$1\n";
   }

##</code><code>##

Message dump:
460 05/12/21 11:41:18:000 Sent FIX Message
Message dump:
461 05/12/21 11:41:23:593 Received FIX message
Message dump:
462 05/12/21 11:41:48:093 Sent FIX Message
Message dump:
463 05/12/21 11:41:55:625 Received FIX message
Message dump:
464 05/12/21 11:42:18:015 Sent FIX Message
Message dump:
465 05/12/21 11:42:27:531 Received FIX message
Message dump: