map3.pl

use strict;
use warnings;
use Text::CSV_XS;
use Data::Printer;

my $csv = Text::CSV_XS->new({ binary => 1, sep_char => "\t" });
open my $fh, "<", $ARGV[0] or die $!;
open my $fh2, "<", $ARGV[1] or die $!;

# 1. 키맵 생성
my %map = ();
while(my $row = $csv->getline($fh)) {
    $map{$row->[0]} = $row->[1];
}

my $count = 0;
while(my $row = $csv->getline($fh2)) {
    $row->[0] = $map{$row->[0]} ? $map{$row->[0]} : $row->[0];
    print join("\t", @{ $row })."\n";
}