#!/usr/bin/env perl

use strict;
use warnings;

{
    my $password;

    sub retrieve_password {
        return $password if defined $password;
        die 'Password not defined';
    }

    sub initialise_password {
        return if defined $password;

        use Term::ReadKey;
        print 'Enter password: ';
        ReadMode('noecho');
        $password = ReadLine(0);
        print "\n";
        ReadMode('restore');
        return;
    }
} 

start();
test();

sub start {
    initialise_password();
}

sub test {
    print 'Testing: ', retrieve_password(), "\n";
}

##</code><code>##

Enter password: 
Testing: some_password