Here 'xxx' is a prefix identifying the particular incarnation of this program. The 'quantities' listed are put in the table, all one one line in the order given. Some quantities may be arrays, in which case all values in the indicated range are included. The log files from which the data comes are listed after the quantities, perhaps with ranges of iterations to use. If the -h flag is present, a single header line will be output first, containing the names of the quantities in the table.
Data comes from records with indexes in the specified ranges within the log files mentioned.
The low bound defaults to one. If no high bound is given, the range extends to the highest index in the log file. If a quantity mentioned is an array with indefinite range, this range must be the same for all log files from which data comes.