#!/usr/bin/perl-w
use Socket;


if ( $#ARGV != 0 ) {
print "Usage: $0 hostname\n";
exit(1);
}

$userinput = $ARGV[0];

if ($userinput =~ m/^(\d+)\.(\d+)\.(\d+)\.(\d+)$/ ) {
	$userinput = $ip;
	$hostname = gethostbyaddr(inet_aton($ip), AF_INET) or die "Can't Resolve $ip: $!\n";
	print $hostname;
}
else {
	$userinput = $name;
	$ipaddr = gethostbyname($name) or die "Can't resolve $name: $!\n";
	$ipaddr = inet_ntoa(inet_aton($name));
	print $ipaddr;
}


##prints this?
$ perl ddlookup.pl wbur.org
Can't resolve : No such file or directory