print uniques from the -b file only

#!/usr/bin/env perl

use strict;
use warnings;
use Getopt::Long ();
Getopt::Long::Configure( 'bundling' );

my %OPTS;
Getopt::Long::GetOptionsFromArray( \@ARGV,
    'a=s' => \$OPTS{A},
    'b=s' => \$OPTS{B},
) or die("Bad options");

open( my $orig, '<', $OPTS{A} )
    or die("Open file-A failed: $!");
open( my $new, '<', $OPTS{B} )
    or die("Open B failed: $!");

my %SEEN;
while (<$orig>) {
    chomp;
    next if( length($_) < 1 );
    $SEEN{$_} = 1;
}
close($orig);

while(<$new>) {
    chomp;
    next if( length($_) < 1);
    next if( exists $SEEN{$_} );
    $SEEN{$_} = 1;
    printf("%s\n", $_);
}

close($new);