#!/usr/bin/perl -w
# start with no existing giant.db file
use strict;
use Fcntl qw(:DEFAULT :flock);
use Storable qw(store_fd fd_retrieve retrieve);
use Data::Dumper;
$Data::Dumper::Deepcopy=1;
$Data::Dumper::Purity=1;
$Data::Dumper::Sortkeys=1;

my %data = ( 1 => 'FEE', 2 => 'FYE',
             3 => 'FOH', 4 => 'FUM', );

sysopen(*DB, "giant.db", O_RDWR|O_CREAT, 0666) or die("sysopen: $!\n");
flock(*DB, LOCK_EX) or die("flock: $!\n");
my $hashref = fd_retrieve(*DB);

# modify the data, do work, etc..
$hashref->{$_} = $data{$_} for sort keys %data;

store_fd($hashref, *DB) or die("store_fd: $!\n");
truncate(*DB, tell(*DB));
close(*DB);