#!/usr/bin/perl
use strict;
use warnings;

if (1)
{
    print "if 1 is exeucuted\n";
}

if (0)
{
    print "if 0 is NOT exeucuted\n";
}

unless (1)
{
    print "unless 1 is NOT exeucuted\n";
}

unless (0)
{
    print "unless 0 is exeucuted\n";
}