#!/usr/bin/perl 
use strict;
use warnings;
use Net::FTP;
my $home="localhost";
my $username="user";
my $password="password";
my $filename='file.txt';

my $file_data;

# $newfile uses $file_data as the backend storage, and is opened read/write.
open my $newfile, '+>', \$file_data;

my $ftp = Net::FTP->new("$home")   or die "Can't connect: $@\n";
$ftp->login($username, $password)  or die "Couldn't login\n";
$ftp->get($filename, $newfile)     or die "Couldn't get $filename\n";

print $file_data;