Encoding type of Perl conversion file

use strict;
use warnings;
use utf8;
use Encode;

sub convert_utf8_to_gbk;
sub convert_gbk_to_utf8;

#----------------------------------------------------------
#  The main function 
#----------------------------------------------------------
my $dir_name = "deal_dir";
unless (-e $dir_name)
{
    
    mkdir $dir_name;
}

my $file_path = "test.m";

convert_utf8_to_gbk($file_path,$dir_name);
#convert_gbk_to_utf8($file_path,$dir_name);

#----------------------------------------------------------
#  Subfunctions 
#----------------------------------------------------------
sub convert_utf8_to_gbk
{
    
    my $utf8_file = shift;
    my $dir_name  = shift;
    my $gbk_file  = $dir_name."/".$utf8_file;
    
    open my $file_rd,'<:encoding(utf8)',$utf8_file;
    open my $file_wr,'>:encoding(gbk)',$gbk_file;
    while(<$file_rd>)
    {
    
        chomp;
        print $file_wr $_,"\n";
    }
    close $file_rd;
    close $file_wr;
}

sub convert_gbk_to_utf8
{
    
    my $gbk_file  = shift;
    my $dir_name  = shift;
    my $utf8_file = $dir_name."/".$gbk_file;
    
    open my $file_rd,'<:encoding(gbk)',$gbk_file;
    open my $file_wr,'>:encoding(utf8)',$utf8_file;
    while(<$file_rd>)
    {
    
        chomp;
        print $file_wr $_,"\n";
    }
    close $file_rd;
    close $file_wr;
}