how ping address from dynamic variable? - bash

Question

I want to ping in a for loop using dynamic names.
When i try ping -c1 -w1 10.0.0.10 > /dev/null it works perfectly, but when i try to change my static adress into a dynamic one, i'll get an error.
declare -A array=([piotr_pc]=10.0.0.10 )
for item in ${!array[*]}
do
file=$(grep $item homesystem/web/openvpn-status.log | tr 'm\n' 'p,')
IFS=','
for x in $file
do
eval $item+=\("$x"\)
done
eval echo \${$item[9]}
if ping -c1 -w1 eval echo \${$item[9]} > /dev/null; then
echo eval echo \${$item[9]} "ONLINE" $NOW
echo "UPDATE openvpn SET status='ONLINE', last_online='$NOW' , Common Name = '${piotr_pc[0]}', Real Address = '${piotr_pc[1]}', Bytes Received = '${piotr_pc[2]}', Bytes Sent = '${piotr_pc[3]}', Connected Since = '${piotr_pc[4]}', Virtual Address = '${piotr_pc[5]}' , Last Ref = '${piotr_pc[8]}' WHERE ip_vpn='${piotr_pc[5]}'"
#mysql -uphptest -pphphaslo openwrt -e "UPDATE openvpn SET status='ONLINE', last_online='$NOW' WHERE ip_vpn='$ip'"
else
eval echo \${$item[9]} "OFFLINE"
#mysql -uphptest -pphphaslo openwrt -e "UPDATE openvpn SET status='OFFLINE' WHERE ip_vpn='$ip'"
fi
done
Result:
root#VigoradoNetwork:/www1# ./ping.sh
10.0.0.10
BusyBox v1.28.3 () multi-call binary.
Usage: ping [OPTIONS] HOST
Send ICMP ECHO_REQUEST packets to network hosts
-4,-6 Force IP or IPv6 name resolution
-c CNT Send only CNT pings
-s SIZE Send SIZE data bytes in packets (default 56)
-t TTL Set TTL
-I IFACE/IP Source interface or IP address
-W SEC Seconds to wait for the first response (default 10)
(after all -c CNT packets are sent)
-w SEC Seconds until ping exits (default:infinite)
(can exit earlier with -c CNT)
-q Quiet, only display output at start
and when finished
-p HEXBYTE Pattern to use for payload
10.0.0.10 OFFLINE
I want to change this 10.0.0.10 with eval echo \${$item[9]} but i dont know how to do this.

Answer 1

I'm not sure if i understood you correctly but following may be helpful if you are running multiple pings to hosts using a hostlist file.
#!/bin/bash
echo "`date` Starting the Ping Check...."
function pingHost () {
hostTarget=${1}
# send stdout/stderr to /dev/null since all we need is the return code
ping -c2 ${hostTarget} >/dev/null 2>&1 &&
echo Host ${hostTarget} is SUCCESS||
echo Host ${hostTarget} is FAILED
}
data=$(<my_hostlist) # Place your hostlist here example "Master_hostlist"
for line in ${data}
do
# call our function and place the call in the background
pingHost ${line} &
done
# wait for all outstanding background jobs to complete before continuing
wait
# [optional] let operator know we're done.
echo "Completed #=> `date`"