#!/usr/bin/perl -w

use strict;
use warnings 'all';

my ($n1, $n2) = @ARGV;
die "Usage:\n$0 <n1> <n2>\n"
  unless defined($n1) && defined($n2);
my $total = 0;
map { $total += $_ } $n1..$n2;
print "Total from $n1 to $n2: $total\n";