#!/usr/bin/perl

use strict;
use warnings;

use Tie::File;
use Data::Dumper;

my $file = "file.txt";
my @lines;

#tie @lines, 'Tie::File', $file || die $!;
tie @lines, 'Tie::File', $file or die $!;

my @tmp = splice @lines;

push @lines, <STDIN>;
push @lines, @tmp;

untie @lines;