Открыт ли порт

nmap 192.168.0.1

telnet 192.168.0.1 80

#!/bin/bash
port=22
host=localhost
ret=`nmap -p$port $host|grep closed`

if [ "${ret}" != "" ] ; then
  echo $port@$host is closed
else
  echo $port@$host is opened
fi

#!/bin/bash

exec 5<>/dev/tcp/ya.ru/80
echo -en "GET / HTTP/1.1\r\nHost: ya.ru\r\nConnection: close\r\n\r\n" >&5
cat <&5

$ nmap localhost -p 80,22

Starting Nmap 6.47 ( http://nmap.org ) at 2015-04-05 01:35 EEST
Nmap scan report for localhost (127.0.0.1)
Host is up (0.000064s latency).
Other addresses for localhost (not scanned): 127.0.0.1
PORT   STATE  SERVICE
22/tcp open   ssh
80/tcp closed http

Nmap done: 1 IP address (1 host up) scanned in 1.06 seconds