1BEGIN { FS = ":" } 2{ if (a) print "a", a 3 if (b == 0) print "b", b 4 if ( c == "0") print "c", c 5 if (d == "") print "d", d 6 if (e == 1-1) print "e", e 7} 8$1 == 0 {print "$1 = 0"} 9$1 == "0" {print "$1 = quoted 0"} 10$1 == "" {print "$1 = null string"} 11$5 == 0 {print "$5 = 0"} 12$5 == "0" {print "$5 = quoted 0"} 13$5 == "" {print "$5 = null string"} 14$1 == $3 {print "$1 = $3"} 15$5 == $6 {print "$5 = $6"} 16