Is this a good approach? Presumably you are putting the hashes in the module for a reason, and for that same reason would it not be better to access the hashes from the outside using a subroutine? This would be a first stage towards encapsulation.

I know it sounds like more work, but it will pay off in the long run.For example:

package XYZ;
{
my %Hash1;
my %Hash2;
my %Hash3;

sub populateHashRoutine {

    # open the file "raw_file.txt"
    open (my $fh, '<', 'raw_file.txt') or die "raw_file: $!";
    
    # Populate %Hash1 %Hash2 %Hash3
    while (<$fh>) {
        # mumble, mumble, mumble 
    }

    close ($fh);
}

sub GetH1 {
    my $key = shift;
    return $Hash1{$key}
}

sub GetH2 {
    my $key = shift;
    return $Hash2{$key}
}

sub GetH3 {
    my $key = shift;
    return $Hash3{$key}
}

}
1;

#main.pl
#========
use XYZ;
XYZ::populateHashRoutine("raw_file.txt");

#How to print Hash1,Hash2,Hash3 values here ?

print XYZ::GetH1('key1'),"\n";
print XYZ::GetH2('key2'),"\n";
print XYZ::GetH3('key3'),"\n";
[download]