---------------- Table 4.3 ----------------
           awk Built-in Variables

FILENAME        name of current input file
FS              field separator character (default blank & tab)
NF              number of fields in input record
NR              number of input record
OFMT            output format for numbers (default %g; see printf(3))
OFS             output field separator string (default blank)
ORS             output record separator string (default newline)
RS              input record seaparator character (default newline)