The predicate described here, unix/1, provides the most commonly
needed access to the operating system. This
minor extension to the Prolog system should be sufficient for most of
your needs. However, you can also extend the Prolog system with
additional C code, including system calls, using the foreign function
interface (see fli-p2f).
The reason for channeling all the interaction with the operating
system through a single built-in predicate, rather than having
separate predicates for each function, is simply to localize the
system dependencies. Admittedly, this makes for more cumbersome
commands, so you may wish to put some clauses such as these in your
prolog.ini file:
cd :- unix(cd).
cd(X) :- unix(cd(X)).
Initialization files are discussed in ref-pro.