

   IIss rruunnnniinngg iinntteerraaccttiivveellyy ??

        interactive()

   VVaalluuee::

        This function returns `TRUE' when is being used inter-
        actively and `FALSE' when not.

   SSeeee AAllssoo::

        `source'

   EExxaammpplleess::

         .First <- function() if(interactive()) x11()

