open $logfh, '<', $logfile;
my $logpos;
while (1) {
  while (my $line = <$logfh>) {
    last unless substr($line, -1) eq "\n"; # May need to tweak for Win32
    print $line;
    $logpos = tell $logfh;
  }
  sleep 1;
  seek $logfh, $logpos, 0;
}