问题
I am wondering how one gets output from SWI-Prolog when invoking it from the shell.
Say I have a simple knowledge base, kb.pl:
dad(elvis, lisaMarie).
dad(john, julian).
I can invoke SWI-Prolog from the shell:
$ swipl --quiet -s kb.pl -t listing
and a listing of my knowledge base is printed to stdout. If I try this:
$ swipl --quiet -s kb.pl -t "dad(elvis, X)"
$ echo $?
0
No output is printed, but I know that it found matches because I get zero when I then query for the return code. Similarly:
$ swipl --quiet -s kb.pl -t "dad(morrisey, X)"
$ echo $?
1
Shows that that the Prolog is correctly failing to find a matching fact.
My question is this: How do I get all the matches to print, so that from the shell I can see output like when I am in the Prolog environment? E.g.
$ swipl --quiet -s kb.pl -t "dad(elvis,X)" --magicdust
X = lisaMarie.
I don't think --quiet is the problem. It is just suppressing prolog startup messages. See SWI-Prolog Command-Line Options
回答1:
Print it yourself, for example with:
$ swipl -q -s kb.pl -t "dad(elvis,X), writeln(X), false"
来源：https://stackoverflow.com/questions/11234469/how-do-i-show-the-results-of-pattern-matching-goals-in-swi-prolog-from-a-shell-i