#!/bin/bash #2013-01-06 14:00:00 wanggy exp #note:ping monitor set -u #set -x ping_fun() {     d_network=192.168.1     echo -n "input the network(default $d_network):"     read network     : ${network:=$d_network}     echo "network:$network"     d_hostip_beg=1     d_hostip_end=254     echo -n "input the hostip(default $d_hostip_beg $d_hostip_end):"     read hostip_beg hostip_end     : ${hostip_beg:=$d_hostip_beg}     : ${hostip_end:=$d_hostip_end}     echo "hostip_beg:$hostip_beg"     echo "hostip_end:$hostip_end"     count=3     for ((hostip=$hostip_beg;hostip<=$hostip_end;hostip++));do             host=$network.$hostip             echo "开始ping检测$host"             ping -c $count $host &>/dev/null                     if [ $? = 0 ];then                             echo "$host is up"                     else                             sleep 3                             ping -c $count $host &>/dev/null                             if [ $? = 0 ];then                                     echo "$host is up"                             else                                     echo "$host is down"                             fi                     fi             done     #echo "执行完毕"     exit 0     }     main()     {     echo "----开始执行ping程序----"     ping_fun     }     main     exit 0