ref: 279f78a86cbff3f526fe1a1debd4d4f5766f96b0
dir: /test/t.null0/
BEGIN { FS = ":" }
{ if (a) print "a", a
if (b == 0) print "b", b
if ( c == "0") print "c", c
if (d == "") print "d", d
if (e == 1-1) print "e", e
}
$1 == 0 {print "$1 = 0"}
$1 == "0" {print "$1 = quoted 0"}
$1 == "" {print "$1 = null string"}
$5 == 0 {print "$5 = 0"}
$5 == "0" {print "$5 = quoted 0"}
$5 == "" {print "$5 = null string"}
$1 == $3 {print "$1 = $3"}
$5 == $6 {print "$5 = $6"}