Merge json files via simple perl script

json-merge.pl

#!/usr/bin/perl
BEGIN { $ENV{PERL_JSON_BACKEND} = 'JSON::PP' }
use JSON; # always uses JSON:PP
use File::Slurp;
use Hash::Merge qw( merge );

use warnings;
use strict;

##
# MAIN
##

MAIN:
{

    my $json = JSON->new->utf8->pretty->sort_by(sub { $JSON::PP::a cmp $JSON::PP::b });
    my $merged = {};

    foreach my $arg ( @ARGV ) {
        my $json_text = read_file( $arg, binmode => ':utf8' );
        my $json_data = $json->decode( $json_text );

        $merged = merge( $merged, $json_data );
    }

    print $json->encode( $merged );
}