The portion that reads the file starting from the bottom:

# Run this portion if user chooses bottom
 
if ($pos =~ /\bbottom\b|\bb\b/){
 
  my $bw = File::ReadBackwards->new( $file ) 
                or die "can't read $file: $!\n" ;
 
  while( defined( $log_line = $bw->readline ) ) {
 
       print $log_line ;
 
}