测试一个网段主机在线情况，禁ping的情况除外

for m in `seq 11 11`
        do
        for n in `seq 2 254`
                do
                ping -c 3 -W 3 192.168.$m.$n &>/dev/null
                if [ $? -eq 0 ];then
                        echo 192.168.$m.$n is up
                else
                        echo 192.168.$m.$n is down
                fi
                done
        done
wait