2.1.1.1 Starting SWI-Prolog on Unix

By default, SWI-Prolog is installed as `swipl'. The command line arguments of SWI-Prolog itself and its utility programs are documented using standard Unix man pages. SWI-Prolog is normally operated as an interactive application simply by starting the program:

$ swipl
Welcome to SWI-Prolog ...
...

1 ?-

After starting Prolog, one normally loads a program into it using consult/1, which may be abbreviated by putting the name of the program file between square brackets. The following goal loads the file https://raw.githubusercontent.com/SWI-Prolog/swipl-devel/master/demo/likes.pllikes.pl containing clauses for the predicates likes/2 :

?- [likes].
true.

?-

Alternatively, the source file may be given as command line arguments:

$ swipl likes.pl
Welcome to SWI-Prolog ...
...

1 ?-

After this point, Unix and Windows users unite, so if you are using Unix please continue at section 2.1.2.