#!/usr/bin/perl -w
#
# Caesar shift decrypting script
# Author: Aleksandr Melentiev <tzapper@users.sf.net>          
# Redistributable under the BSD License

use strict;
use warnings;

print "Enter encrypted string:\n";
chomp(my $cipher = <STDIN>);

my @alphabet = ('A' .. 'Z');
for (@alphabet) {
        my $text = $cipher;
        my $rot = join("", @alphabet);
        eval "\$text =~ tr/a-zA-Z/$rot/, 1" or die $@;
        print "ROT: $text\n";
        push(@alphabet, shift(@alphabet));
}