#!/usr/bin/ruby -w
# Classical rot13 filter.
#
# File is named "caesar" for Caesar cipher to avoid prefix conflict with
# the rotate scripts.

ARGF.each_char{|c|
   x = c.ord
   print ((x > 64 && x < 91) ||
          (x > 96 && x < 123) ? ((x % 32 + 12) % 26 + (x & ~31) + 1).chr
                              : c)
}