Discovering the XOs local timezone in a bash script

[Richard A. Smith]

I've added a new feature in my power logging processor that allows the 
plotting of power input vs time of day.  To do this I have to know the 
local timzone so I can translate the UTC datestamp back to the local time.

`date` says the XO's timezone is set to UTC so I'll have to get it from 
somewhere else.

Can someone give me a quick rundown of how we are managing timezones so 
I know what to look at to determine this?

-- 
Richard A. Smith  <richard at laptop.org>
One Laptop per Child