通过Ping命令监控主机是否存活，只要一次ping通则为正常，如果ping失败则继续ping，三次不通就认为主机宕机或网络有问题，这时就可以发送邮件告警了。
方法一：
说明：如果判断的机器数量不多，可以每台机器Ping三次判断
#! /bin/bash
if [ -e /tmp/c.txt ];then
rm -rf /tmp/c.txt
touch /tmp/c.txt
else
touch /tmp/c.txt
fi
if [ -e /tmp/d.txt ];then
rm -rf /tmp/d.txt
touch /tmp/d.txt
else
touch /tmp/d.txt
fi
for i in `seq 100 105`
do
ip=192.168.2.$i
ping -c 3 $ip > /dev/null 2>&1
if [ $? -eq 0 ];then
echo $ip "is on line" >> /tmp/c.txt
else
echo $ip "is offline" >> /tmp/d.txt
fi
done
方法二：
说明：将错误次数放到fail_count变量来判断是非Ping失败三次
#! /bin/bash
if [ -e /tmp/c.txt ];then
rm -rf /tmp/c.txt
touch /tmp/c.txt
else
touch /tmp/c.txt
fi
if [ -e /tmp/d.txt ];then
rm -rf /tmp/d.txt
touch /tmp/d.txt
else
touch /tmp/d.txt
fi
for i in `seq 100 105`
do
ip=192.168.2.$i
fail_count=0
for ((i=1;i<=3;i++))
do
if ping -c 1 $ip > /dev/null;then
echo "$ip is online" >> /tmp/c.txt
break
else
#echo "$ip ping is offline $i"
let fail_count++
fi
done
if [ $fail_count -eq 3 ];then
echo "$ip is offline" >> /tmp/d.txt
fi
done
方法三：
说明：将错误ip放到数组里面判断是否Ping失败三次
#! /bin/bash
if [ -e /tmp/c.txt ];then
rm -rf /tmp/c.txt
touch /tmp/c.txt
else
touch /tmp/c.txt
fi
if [ -e /tmp/d.txt ];then
rm -rf /tmp/d.txt
touch /tmp/d.txt
else
touch /tmp/d.txt
fi
for i in `seq 100 105`
do
ip=192.168.2.$i
num=1
while [ $num -le 3 ]
do
if ping -c 1 $ip > /dev/null;then
echo "$ip is online" >> /tmp/c.txt
break
else
# echo "$ip ping is offline $num"
fail_count[$num]=$ip
let num++
fi
done
if [ ${#fail_count[*]} -eq 3 ];then
echo "${fail_count[1]} is offline" >> /tmp/d.txt
fi
done
方法四：
说明：利用for循环，因为continue，如果ping通就跳出循环，，如果不跳出就会打印ping失败
#! /bin/bash
if [ -e /tmp/c.txt ];then
rm -rf /tmp/c.txt
touch /tmp/c.txt
else
touch /tmp/c.txt
fi
if [ -e /tmp/d.txt ];then
rm -rf /tmp/d.txt
touch /tmp/d.txt
else
touch /tmp/d.txt
fi
ping_success_status(){
if ping -c 1 $ip > /dev/null;then
echo "$ip is online" >> /tmp/c.txt
continue
fi
}
for i in `seq 100 105`
do
ip=192.168.2.$i
ping_success_status
ping_success_status
ping_success_status
echo "$ip is offline" >> /tmp/d.txt
done
下面这个截图，跟上面的图片有一点区别：
ifconfig |awk -F [:a-Z" "]+ ‘NR==2{print $2}‘可以获取IP地址
本文参考一下文章：
http://12100846.blog.51cto.com/12090846/1863259
原文地址：http://5609180.blog.51cto.com/5599180/1864788
