[Novice] How to write command line tools?

[黃俊傑(Chun-Chieh Huang)]

Dear all,
    I'm a novice to GNUstep, but I wrote a simulation program which
was running on OPENSTEP 4.2. Now I plan to port it to Linux
GNUSTEP. But I have some questions about GNUstep. 
    I read a lot of GNUstep manuals and documents. But there is not
much documents for command line tools, I mean, programs which use only
Foundation classes. The examples are only for GUI. But only Foundation
classes are needed for my simulation program. I think I don't need
NSApplication instance, right? But I still don't know the complete
structures for command line tools. 
    Is there anybody kind of telling me what the structures are, or
giving me some command line examples? Thank you very much.

Chun-Chieh Huang
-- 
Chun-Chieh Huang(黃俊傑)       | E-mail: jjhuang AT cm.nctu.edu.tw
Department of Computer Science | 
National Tsing Hua University  | MIME/ASCII/PDF/PostScript are welcome!
HsinChu, Taiwan                | NO MS WORD DOC FILE, PLEASE!