I am having a total brain fart... complete and total. This is part R, Part Statstitics, Part "My Brain is on vacation apparently." Ok I have a time series I need to LOG and DIFF for ARIMA with Regressors. Say 100 data points. Obviously when I diff the series once I get 98 data points now. So what is the appropriate way to handle that now. Part B (This is where I am having a fundamental brain fart). Given that I have Logged and Diff'ed the original Time Series and I want to get a forecast, how do I apply that back to my original data? I am having a mental implosion right now (Just got back from vacation.) I am just not wrapping my head around forecasting in R against transformed data (For stationary purposes). Total brain meltdown (mmmm grilled cheese sounds good...) Anyone have a basic shell script I can look at for reference... not connecting dots today.... Idgarad -- "Who is John Galt?" [[alternative HTML version deleted]]