Emacs offers convenient variables for customizing indentation styles:
indent-tabs-mode and sws-tab-width. For many programming modes, a user can
set these variables globally, and they will automatically be applied to
different file formats. Of course, these can be customized per-mode with
hooks.

However, shell-mode does not appear to respect these variables, only
responding to its own internal variable names sh-basic-offset and
sh-indentation. In the future, could shell-mode please automatically
default these to follow sws-tab-width, so that fewer individual modes
require specific configuration?

Here's my .emacs for reference:

https://github.com/mcandre/dotfiles/blob/master/.emacs#L59-L60

-- 
Cheers,
Andrew