#!/usr/bin/perl
use warnings;
use strict;

our @data = qw(webpage1 webpage2);

print "Webpage needed: ";      # <STDIN> flushes output buffers
chomp(my $response = <STDIN>); # <STDIN> instead of <> in case they
                               # add command line arguments

push @data, $response unless grep { $_ eq $response } @data;

print "$_\n" for @data;