This command enables the tracing of production activity for individual productions. Both firings and retractions are printed. If no production-names are given, this command lists the productions currently being traced. If one or more production-names are given, tracing is enabled for those productions. Tracing persists until disabled by an unpwatch command, or until the production is excised.
This command is orthogonal to the watch -firings mechanism. See the watch command for more information.