服务器存活脚本分析
在linux系统中，可以使用ping命令检测主机状态，根据返回的状态信息，判断当前主机是活动，还是已经宕机了。
下面是判断网络中主机存活状态的shell第一个脚本，具体如下所示：
方法一：使用for循环
[root@tianyun ~]# vim ping_count3_1.sh
#!/usr/bin/bash
ip_list=”10.18.40.1 10.18.42.127 10.18.42.8 10.18.42.5”
#循环ip_list中的ip各一次
for ip in $ip_list
do
#对每个ip各ping三次判断存活状态
for count in {1..3}
do
ping –c1 –W1 $ip &>/dev/null
#如果ping通就退出，ping不通统计失败的次数
if [ $? –eq 0 ];then
echo “$ip ping is ok.”
break
else
echo “$ip ping is failure: $count”
#利用数组的方式统计失败的次数
fail_count[$count]=$ip
fi
done
#判断fail_count数组的元素个数，如果个数为3，说明这个ip是不通的
if [ ${#fail_count[*]} –eq 3 ];then
echo “${fail_count[1]} ping is failure!”
unset fail_count[*]
fi
done
第一种方法执行结果如下：
[root@tianyun ~]# chmod a+x ping_count3_1.sh
[root@tianyun ~]# ./ping_count3_1.sh
10.18.40.1 ping is ok.
10.18.42.127 ping is ok.
10.18.42.8 ping is failure: 1
10.18.42.8 ping is failure: 2
10.18.42.8 ping is failure: 3
10.18.42.8 ping is failure!
10.18.42.5 ping is failure: 1
10.18.42.5 ping is failure: 2
10.18.42.5 ping is failure: 3
10.18.42.5 ping is failure!
方法二：使用while循环
[root@tianyun ~]# vim ip.txt
10.18.40.1
10.18.42.127
10.18.42.4
10.18.42.8
While循环脚本如下：
[root@tianyun ~]# vim ping_count3_1.sh
#!/usr/bin/bash
#ip_list=”10.18.40.1 10.18.42.127 10.18.42.8 10.18.42.5”
#循环ip_list中的ip各一次
While read ip
do
#对每个ip各ping三次判断存活状态
for count in {1..3}
do
ping –c1 –W1 $ip &>/dev/null
#如果ping通就退出，ping不通统计失败的次数
if [ $? –eq 0 ];then
echo “$ip ping is ok.”
break
else
echo “$ip ping is failure: $count”
#利用数组的方式统计失败的次数
fail_count[$count]=$ip
fi
done
#判断fail_count数组的元素个数，如果个数为3，说明这个ip是不通的
if [ ${#fail_count[*]} –eq 3 ];then
echo “${fail_count[1]} ping is failure!”
unset fail_count[*]
fi
done <ip.txt
第二种方法执行结果如下：
[root@tianyun ~]# ./ping_count3_1.sh
10.18.40.1 ping is ok
10.18.42.127 ping is ok
10.18.42.4 ping is failure: 1
10.18.42.4 ping is failure: 2
10.18.42.4 ping is failure: 3
10.18.42.4 ping is failure!
10.18.42.8 ping is failure: 1
10.18.42.8 ping is failure: 2
10.18.42.8 ping is failure: 3
10.18.42.8 ping is failure!
下面是判断网络中主机存活状态的shell第二个脚本，具体如下所示：
[root@tianyun ~]# vim ip.txt
10.18.40.1
10.18.42.127
10.18.42.4
10.18.42.8
[root@tianyun ~]# vim ping_count3_2.sh
#!/usr/bin/bash
while read ip
do
#定义失败次数的初值，计算失败的次数
for i in {1..3}
do
ping –c1 –W1 $ip &>/dev/null
if [ $? –eq 0 ]; then
echo “$ip ping is ok.”
break
else
echo “$ip ping is failure: $i”
let fail_count++
fi
done
if [ $fail_count –eq 3 ]; then
echo “$ip ping is failure!”
fi
done <ip.txt
执行结果如下所示：
[root@tianyun ~]# chmod a+x ping_count3_2.sh
[root@tianyun ~]# ./ping_count3_2.sh
10.48.40.1 ping ok.
10.18.42.127 ping is ok.
10.48.42.4 ping is failure: 1
10.48.42.4 ping is failure: 2
10.18.42.4 ping is failure: 3
10.18.42.4 ping is failure!
10.18.42.8 ping is failure: 1
10.18.42.8 ping is failure: 2
10.18.42.8 ping is failure: 3
10.18.42.8 ping is failure!
下面是判断网络中主机存活状态的shell第三个脚本，具体如下所示：
[root@tianyun ~]# vim ping_count3_3.sh
#!/usr/bin/bash
#定义函数，执行函数
ping_success(){
ping –c1 –W1 $ip &>/dev/null
if [ $? –eq 0 ];then
echo “$ip is ok.”
Continue
fi
}
While read ip
do
ping_success
ping_success
ping_success
echo “$ip ping is failure!”
done <ip.txt
执行结果如下：
[root@tianyun ~]# chmod a+x ping_count3_3.sh
[root@tianyun ~]# ./ping_count3_3.sh
10.18.40.1 is ok.
10.18.42.127 is ok.
10.18.42.4 ping is failure!
10.18.42.8 ping is failure!
