#!/usr/bin/perl

use strict; # https://perlmonks.org/?node_id=11148149
use warnings;
use Storable;

my $filename = '/tmp/d.11148149.testfile';

my $hashref = eval { retrieve $filename } || {};
use Data::Dump 'dd'; dd $hashref; # was
$hashref->{+time} = 1; # do something with $hashref...
use Data::Dump 'dd'; dd $hashref; # is now
store $hashref, $filename;