#!/usr/bin/env perl
use warnings;
use strict;
use JSON;

my $history = 'history.json';

open my $fh, '<', $history or die $!;
    my $utf8_encoded_json_text = readline $fh;
    my $hashref = decode_json $utf8_encoded_json_text;
close $fh;

$hashref->{key_1} = [ 2, 3, 6, 11 ];

open $fh, '>', $history or die $!;
    $utf8_encoded_json_text = encode_json $hashref;
    print $fh $utf8_encoded_json_text;
close $fh;