linux shell 判断主机三次存活之批量探测

在生产环境中，需要查看主机在线情况，之前都是采用执行一次ping命令的方式去操作，会丢失某些存活主机，故改进了脚本采用ping三次的方式进行操作。

#for 语句
#！/bin/bash
ip_list="192.168.10.11 192.168.10.12 192.168.10.13 192.168.10.14 192.168.10.15 192.168.10.16 192.168.10.17 "
for ip in $ip_list
do          
        for count in {1..3}
        do  
                ping -c1 -W1 $ip >/dev/null
                if [ $? -eq 0 ];then
                        echo "$ip is ok"
                        break; 
                else
                        #echo "$ip ping faulure:$count"
                        failcount[$count]=$ip
                fi 
        if [ ${#failcount[*]} -eq 3 ];then
                echo "${failcount[1]} is failure"
                unset failcount[*] 
        fi
        done
done

#while语句后台运行
#！/bin/bash
while read ip
#for ip in $ip_list
do
{
        for count in {1..3}
        do
                ping -c1 -W1 $ip >/dev/null
                if [ $? -eq 0 ];then
                        echo "$ip is ok"
                        break;
                else
                        #echo "$ip ping faulure:$count"
                        failcount[$count]=$ip
                fi
        if [ ${#failcount[*]} -eq 3 ];then
                echo "${failcount[1]} is failure"
                unset failcount[*]
        fi
        done
}&
done <ip.txt
wait
#后台运行可使脚本运行效率大大提高