Similarly in explicit mode, the table used to specify station, channel, and time ranges might be from a different database. Be a little noisy during the construction of the output. Chatter verbosely during the process. The trexcerpt parameter file is fairly complex, so it should be edited with caution. It is primarily a method of configuring the program, rather than a means to specify a single run.
Many entries specify a list of views, rather than a single view.
This is an attempt to accomodate more and less complete databases. The first view which when evaluated has at least one row is used. The wfname value specifies a default form for the output waveform files. The start and stop values are default expressions used when no command line values are provided. A join containing site, sitechan, sensor and instrument facilitates propagating fields from these tables into the output, and is required for some output types like autodrm and sac.