You can turn on tracing for backward chaining from Lisp by running
(clog:logic '(and (clog:unleash) (trace)))
There are no command line tools for tracing forward chaining rules directly, but the RHS of each rule is run using a backward chaining rule with the same name, so they also appear when you trace backward chaining.
You could also add tracing to forward rules by defining a Meta Rule Protocol, for example like the explanation facility described in A Simple Explanation Facility.
KnowledgeWorks and Prolog User Guide (Macintosh version) - 6 Dec 2011