shell ping

#!/bin/bash

PATH=/bin:/sbin:/usr/bin:/usr/sbin:/usr/local/bin:/usr/local/sbin:~/bin
export PATH

ip="192.168.11."

for i in `seq 100 110`
do
ping -w 1 -c 1 "$ip$i" &>/dev/null
if [[ $? == 0 ]]
then
echo "$ip$i is up" >>/tmp/1.txt
else
echo  "$ip$i is down" >>/tmp/1.txt
fi
done