Reads one or more variables from the opened
data file.
PAGE reads variables from the data file in
sequence and assigns them to the variable
names on the dot command line. If the data
file line ends before all the variables on
the .RV line have been used, all remaining
variable are set to null. If there is more
data on the data file line after all
variables have been filled, the remainder of
the data file line is ignored.
The Data File may contain .FI commands for
joining data files by reference.