[R] How to step through a demo

[Ron Burns]

I have just started to learn R on linux in an X-terminal  "command line" 
environment at the R prompt ">".  When I try to run a demo it just races 
through all the steps and graphics leaving me with only the last few 
commands and results in the  terminal window and a window with the last 
graphic.  Is there a way to step through the demo command-by-command 
graphic-by-graphic, or, if not, how should I make use of (i.e. run) the 
demo? 

Thanks for any help