三种判断端口存活的方法和链接200的判断方法

[root@localhost ~]# (echo "quit") | telnet 127.0.0.1 22 #()放到子shell执行
Trying 127.0.0.1...
Connected to 127.0.0.1.
Escape character is '^]'.
Connection closed by foreign host.

[root@ryzc32 opt]# cat telnet.sh
#!/bin/bash
JG=`echo -e "\n" | telnet  192.168.1.30 22 | grep Connected | wc -l`
if [ "$JG" == 1 ];then
echo "0"    #如果JG等于1，端口为通，输出0
else
echo "1"    #如果JG等于0，端口不通，输出1
fi

[root@localhost opt]# cat nmap.sh
#!/bin/bash
namp=`nmap 192.168.100.50 -p 22 | grep open | wc -l`
if [ "$namp" == 1 ];then
echo 0
else
echo 1
fi

[root@localhost opt]# cat nc.sh
#!/bin/bash
nc -w 5 192.168.100.50 22 && echo 0 || echo 1

[root@mndg248 opt]# cat url_mon.sh
#!/bin/bash
wget -T 10 -c -q --spider www.baidu.com && RETVAL=$?
if [ "$RETVAL" == 0 ];then
echo "0"
else
e    cho "1"
fi