host

早期freebsd实现

#!/bin/sh
#------------------------------------------------------------------
#	host
#	input ->  numerical representation of an Internet address
#	output -> textual representation of the host at the address
#------------------------------------------------------------------
/usr/local/bin/query -h  `echo $1 |
/bin/awk  '
{
	n = split($1, oct, ".")
	if (n != 4)
		printf("127.0.0.1.in-addr.arpa.\n")
	else {
		printf("%s.%s.%s.%s.in-addr.arpa.\n", oct[4], oct[3], oct[2], oct[1])
	}
}' ` -t ptr |
/bin/awk '
 {
 	if (($1 == "domain") && ($2 == "name")) {
 		printf("%s\n", $4)
 		exit
 	}
 }'