shell for in loop with multible variable [duplicate] - bash

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Iterate over two arrays simultaneously in bash
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in my question i learn to use loops and with you help I final a installation script for multible instance of a software. thank you very much :)
now I try to automatic setup the configuration files by using sed. For this i need multible variables in a loop.
I read from the system the IP-Adresses and the hostnames for the IP's (PTR)
IPADDR=`ifconfig | awk '{print $2}' | egrep -o '([0-9]+\.){3}[0-9]+'|grep -v 127.0.0.1`
for ipaddr in ${IPADDR[#]}; do echo $ipaddr; done
for iphost in ${IPADDR[#]}; do host $iphost |grep pointer | awk '{print $NF}' RS='.\n'; done
my Script know, there ar 3 IP's, know the IP-Addresses and the Hostnames.
the numbers of IP (3) are now my 001 002 003. this running well.
if I like to edit the config files with sed, I need the 3 variable to do this.
command anyname-001 -some -parameter in my case is a copy to a path. my path is now
/etc/anyname-001, /etc/anyname-003 and /etc/anyname-003
by using sed I need also the 3 IP-Addresses and the 3 hostnames.
sed -i 's/IPADDR/'${ipaddr}'/g' /etc/anyname-${number}/config.cfg
sed -i 's/HOSTNAME/'${hostname}'/g' /etc/anyname-${number}/config.cfg
how can I bring my loop to this with all variables on same time. T try many things. I found nested loops but it not work
001 >> IP:a.a.a.a >> hostname aaa.aaa.aa
002 >> IP:b.b.b.b >> hostname bbb.bbb.bb
003 >> IP:c.c.c.c >> hostname ccc.ccc.cc
Thank you

Answer 1

Assuming the length of both of your arrays HOSTNAME and IPADDR are the same, then you can loop over their elements via indexes in one run.
The length of an array is calculated by using the '#' in the array variable, for example as:
echo ${#HOSTNAME[#]}
So, overall your code would look like something:
count=${#HOSTNAME[#]}
for (( i=0; i<${count}; i++ ));
do
echo ${HOSTNAME[$i]};
echo ${IPADDR[$i]};
((j=i+1));
sed -i 's/IPADDR/'${IPADDR[$i]}'/g' /etc/anyname-${j}/config.cfg
sed -i 's/HOSTNAME/'${HOSTNAME[$i]}'/g' /etc/anyname-${j}/config.cfg
done