Bash scripting Array concepts

Question

I have two separate lists. One contains 1000 hostnames and other contains 1000 associated IP's for that hosts. I need to generate config entries and push to my config file to add all hosts under our monitoring environment.

 #!/bin/bash Enter the hostnames readarray hosts Enter the IP's readarray IP 

How should I iterate one by one in a loop like below? I know how to iterate single array by using for i in "${hosts[@]}", but in the case of two separate lists, how to achieve iteration?

 echo -e "\nObject host \""$hosts"\"{" import = \""generic-service"\" address = \""$IP"\" group = \""Mom1-Ping"\" "\n}" >> /etc/icinga2/zones.d/mom2/AP.conf 

Example of first list (List 1):

sjc02-mfg-api01.example.com sjc02-mfg-api02.example.com sjc02-mfg-api03.example.com 

upto 1000 hosts

Example of second list (List 2):

10.20.2.22 10.20.2.23 10.20.2.24 

up to to 1000 IP's

Expected output:

 Object host "sjc02-mfg-api01.example.com" { import = "generic-service" address = "10.20.2.22" group = "Mom01-Ping" } Object host "sjc02-mfg-api02.example.com" { import = "generic-service" address = "10.20.2.23" group = "Mom01-Ping" } Object host "sjc02-mfg-api03.example.com" { import = "generic-service" address = "10.20.2.24" group = "Mom01-Ping" } ..........like this I need to generate to all 1000 hosts............. 

Answer 1

Combine your both lists together using paste. You can do it as follows:

#!/bin/bash paste list1 list2 | while IFS=$'\t' read -r L1 L2 do echo " Object host ${L1} { import = "generic-service" address = ${L2} group = "Mom01-Ping" }" done 

output:

Object host sjc02-mfg-api01.example.com { import = generic-service address = 10.20.2.22 group = Mom01-Ping } Object host sjc02-mfg-api02.example.com { import = generic-service address = 10.20.2.23 group = Mom01-Ping } Object host sjc02-mfg-api03.example.com { import = generic-service address = 10.20.2.24 group = Mom01-Ping } 

Answer 2

You can iterate over the indices of the pair of arrays:

a1=(foo bar baz) a2=(one two three) for ((i=0; i < "${#a1[@]}"; i++)); do echo "${a1[i]} => ${a2[i]}" done 

where ${#a1[@]} is the size of the a1 array