Why YiNoDz?

YINODZ are the options given when upgrading a package in linux and there is an existing configuration file for that package. The upgrade system then asks what you want to do with the files:

Configuration file `/etc/bash.bashrc'
==> Modified (by you or by a script) since installation.
==> Package distributor has shipped an updated version.
What would you like to do about it ? Your options are:
Y or I : install the package maintainer's version
N or O : keep your currently-installed version
D : show the differences between the versions
Z : start a shell to examine the situation
The default action is to keep your current version.
*** bash.bashrc (Y/I/N/O/D/Z) [default=N] ?