I thought I would post this piece of code since it has been laying around for quite a while.

ld-preload-reverse is a LD_PRELOAD library that overrides the most common
functions for writing text to a terminal, and reverses their output:

Looks like this:

tobbez@sagiri ~/dev/ld-preload-reverse $ LD_PRELOAD=./ld-preload-reverse.so bash
 $ esrever-daolerp-dl/ved/~ irigas@zebbotls
GNIYPOC  elifekaM  EMDAER  c.esrever-daolerp-dl  os.esrever-daolerp-dl
 $ esrever-daolerp-dl/ved/~ irigas@zebbotcat Ma elifek
os.esrever-daolerp-dl :lla

c.esrever-daolerp-dl :os.esrever-daolerp-dl
c.esrever-daolerp-dl os.esrever-daolerp-dl o- derahs- CIPf- ldl- llaW- ccg

:naelc YNOHP.
os.esrever-daolerp-dl f- mr
 $ esrever-daolerp-dl/ved/~ irigas@zebbottixe

It’s licensed under the Eiffel Forum License 2, and you can find the code here.