[ns] sending xgraph output to ps file instead of X?

[Tan Su Wei <swtan@mmu.edu.my>]

Dear all,
    I would like to send the output of xgraph to a file instead of X.
Currently, I can do this with the xgraph windows, using the hardcopy
button.
    I'm running a set of simulation, and want to plot the trace result
from each set of simulation straight into a postscript file.
    I read the xgraph manual page, it seem by using the Device
& Disposition option in the trace file, the problem can be solved. But I
tried to put both option in the trace file, and running xgraph with the
trace file, I still get the xgraph window pop up and no postscript file
appear.
    I also tried the xgraph command line option -device and -O, though
the ps file is created, a core was dump. I'm running linux redhat 6.1,
and xgraph 12.1.

    Can some one show me the way? Thanks.

regards
Tan Su Wei