Perl: 13 line ROT-13

rot13.pl

#
# Perl - ROT-13 
#
# guidjos

use warnings;
use strict;

die "\n\n\t $0 [-e | -d] [text]\n" unless @ARGV > 1;
my $option	= shift;
my $_		= join " ", @ARGV;
my $key;

die "\n\n\tOption is \"-e\" (encrypt) or \"-d\" (decrypt)\n\n" unless $option eq "-e" or $option eq "-d";

$\ = "\n\n";
print "\n\n\t";
$key = "nopqrstuvwxyzabcdefghijklm";

$option eq "-e" and eval "tr/a-z/$key/;";
$option eq "-d" and eval "tr/$key/a-z/;";

print;