[EMBOSS] fdrawgram, no prompting

[C.A. Russell]

I'm trying to automate the plotting of a large number of trees. I'm using 
the following command to plot trees

fdrawgram -intreefile infile -plotfile outfile.ps -previewer n -plotter l 
-auto

Everything is good except that I can't figure out how to stop fdrawgram 
from prompting me with

"Is the tree ready to be plotted? Type Y or N:"

I thought that -auto should make the assumption that indeed the tree is 
ready to be plotted but I still get prompted. Can anyone tell what 
arguments to pass to fdrawgram to make it not prompt me?

If it makes a difference I'm running OS X 10.4.9

Many thanks

Colin