use strict;
use warnings;

use constant {
    FILE_A  => './kma',
    FILE_B  => './kma2',
};

my %a_hash;

my @a_array;
my @b_array;

open my $a_fh, "<", FILE_A;
while (<$a_fh>) {
chomp;
my ($key, $value) = split '=', $_, 2;
$a_hash{$key} = $value;
}

open my $b_fh, "<", FILE_B;
while (<$b_fh>) {
chomp;
my ($key, $value) = split '=', $_, 2;
$a_hash{$key} = $value;
}

open my $c_fh, ">", FILE_A or die $!;
print $c_fh "$_=$a_hash{$_}\n" for (keys %a_hash);