uno = uno 
due = dos
tre = tres
quattro = quatro
cinque = cinco
sei = seis
sette = siete
otto = ocho
nouve = nueve
dieci =diez

##</code><code>##

uno = un
due = deux
tre = trois 
quattro = quatre
cinque = cinq
sei = six
sette = sept
dieci = dix

##</code><code>##

uno => uno, un
due => dos , deux
tre => tres , trois
quattro => quatro, quatre
cinque => cinco , cinq
sei => seis, six
sette => siete, sept
dieci => diez, dix

##</code><code>##


use strict;
use warnings;

use Data::Dump qw(dump); 
use Storable; #don't know this yet but let's try soon.

my %hash;

#opening my file handles; adding recommendations with naming extentions
open my $in, '<',"./test_data.txt" or die ("can't open the file:$!\n");
open my $in1,'<',"./test_data1.txt" or die ("can't open file : $!\n");
open my $out ,'>' ,"./test_data_out.txt" or die "can't open the file for write:$!\n";
open my $out1 ,'>',"./test_data_out1_no_match.txt" or die "can't open file for write:$!\n";
 
while (<$in>){
    chomp;
    my ($key, $value)= split (/\s*=\s*/); #greedy matching for better regex coverage as per Ken
    $hash{$key}=$value;
    }
close $in;

while (<$in1>){
   chomp;
   my ($key,$value) = split (/\s*=\s*/); #splits row into 2 col. 
  
        #checks for keys that EXIST in both then prints...?
        if (exists $hash{$key}){
        print $out "$key => $hash{$key} , $value \n";
        } else {
        print $out1 "$key => $value \n";
        }
} 
close $in1;
close $out;
close $out1;