ARGC number of command-line arguments
ARGV array of command-line arguments
FILENAME name of current input file
FNR record number in current file
FS input field separator (default= space and tab characters)
NF number of fields in input line
NR number of input lines read so far
OFMT output format for numbers (default=%.6)
OFS output field separator (default=space)
ORS output line separator (default=newline)
RS input line separator (default=newline)
RSTART index of first character matched by match()
RLENGTH length of string matched by match()
SUBSEP subscript separator (default="\034")