#!/usr/bin/perl

use strict;
use warnings;
use Tie::File;

my $id_from_form=5;
my $move="up";
my $flat_file = './flat.file';

tie my @array, 'Tie::File',$flat_file or die $!;
chomp @array;
my ($index) = grep{$array[$_] =~ /^$id_from_form\*\*/}(0..$#array);
print $index,"\n";
if($move eq 'up'){
  my $elem = $array[$index];
  $array[$index] = $array[$index-1];
  $array[$index-1] = $elem;
}
else{
  my $elem = $array[$index];
  $array[$index] = $array[$index+1];
  $array[$index+1] = $elem;
}
$_ . "\n" for @array;
untie @array;