Prolog - XSB Execute Prolog in Command Line and drop result in file.

Here I would like to discuss on How to execute a Prolog Expression, and store the result in a file,
Also Execute the prolog Expression through Comand line,

Solution:
For implementing the Prolog, I have chosen XSB:
Once the XSB is installed, I kept the XSB/bin folder in System variables, so that I can execute from command line from any locations.

WRITE Operation in Prolog:
For writing the content to a file, Similar to any Streams in programming Language we can set the Streams here as follows.

open('RESULT_1380695160492.txt', write, H),
    tell(H),
    write('Hello World'),
    told.

First we open a file and assigned to a Handler H.
Method tell(H) : it will change the Stram to the provided Handler H.
told: Works as Stream writing is completed, and it will close the file.

Example : Evaluation of recursive Expression to a File.

Find the indirect paths from the provided direct paths.
Expression:

File Name : direct.P
direct(a,b).
direct(b,c).
direct(c,d).
direct(d,e).
indirect(X,Y):-direct(X,Y).
indirect(X,Y):-direct(X,Z), indirect(Z,Y).

calc :- open('TEST_RESULT_FILE.text', write, H),
tell(H),
calcResult,
told,halt.

calcResult :- indirect(X,Y),
    write(X),write('   '), write(Y),nl,
    fail.

calcResult.

To execute this program from command line, Execute the following command.

xsb -e [direct], calc.    //Here direct is teh file name.

It will Execute the Command and store the result in the file Called : TEST_RESULT_FILE.text

The result is as follows.
a   b
b   c
c   d
d   e
a   c
a   d
a   e
b   d
b   e
c   e

Regards

Asker Ali M