unix(cd(+Path)) changes the working directory of Prolog
(and of Emacs, if running under the editor interface) to that
specified by Path, which should be an atom corresponding to a
legal directory. If Path is not specified, unix(cd)
changes the working directory of Prolog (and of Emacs if running under
the editor interface) to your home directory.
Note that the <ESC> x cd Path and <ESC> x cd commands under Emacs have the same effect as this, except that Emacs also provides filename completion.