What fletch said. Meanwhile, just because I feel like playing:

#!/usr/bin/perl -w
use strict;
use Term::ReadKey;

my %hashed;
@hashed{'a'..'z'} = 1..26;
my @mixed = keys %hashed;

ReadMode "raw";
while (my $key = lc(ReadKey(0))){
    last if ord($key) == 27;    # You can get out if you can figure it
+ out
    print $mixed[ord($key)-97];
}
ReadMode "normal";
[download]

Update: Added a statement to reset the tty to normal. Ya gotta do that after you've been insane. :)