caesar is a really simple caesar cipher.
in the caesar directory run the command
#+BEGIN_SRC sh make #+END_SRC
#+BEGIN_SRC sh ./caesar -f test2.txt -s 10 #+END_SRC
#+RESULTS:
QXE Owkmc sc Pboo!
#+BEGIN_SRC sh ./caesar -f test2.txt -s 10 | ./decrypt #+END_SRC
#+RESULTS: | GNU | Emacs | is | Free! | | | | | |