Propellor often generates some shell code to run. 
Examples include Propellor.Bootstrap, but also things like 
userScriptProperty where a shell command has to be built that can be fed
into sudo.

The current code for this is just all strings and easy to make mistakes in.
It would be good to integrate <http://hackage.haskell.org/package/shell-monad>
(or a similar library) as a way to generate shell code. --[[Joey]]

<http://hackage.haskell.org/package/turtle> might be another good option
--[[Joey]]
