Bash - Break up returned value from MySQL query

Question

I am trying to break up a returned value from a mysql call in a shell script. Essentially what I have done so far is query the database for IP addresses that I have stored in a specific table. From there I store that returned value into a bash variable. The code is below:

#!/bin/bash

# This file will be used to obtain the system details for given ip address

retrieve_details()
{
  # get all the ip addresses in the hosts table to pass to snmp call
  host_ips=$(mysql -u user -ppassword -D honours_project -e "SELECT host_ip FROM hosts" -s)
echo "$host_ips"
  # break up the returned host ip values

  # loop through array of ip addresses
  # while [  ]
  # do

     # pass ip values to snmp command call

     # store details into mysql table host_descriptions

  # done
}

retrieve_details

So this returns the following:

192.168.1.1
192.168.1.100
192.168.1.101

These are essentially the values I have in my hosts table. So what I am trying to do is break up each value such that I can get an array that looks like the following:

arr[0]=192.168.1.1
arr[1]=192.168.1.100
arr[2]=192.168.1.101
...

I have reviewed this link here: bash script - select from database into variable but I don't believe this applies to my situation. Any help would be appreciated

Santhy K · Accepted Answer · 2016-03-02 04:20:46Z

1

host_ips=($(mysql -u user -ppassword -D honours_project -e "SELECT host_ip FROM hosts" -s));

outer () will convert that in array. But you need to change your IFS (Internal Field Separator) to a newline first.

IFS=$'\n';
   host_ips=($(mysql -u user -ppassword -D honours_project -e "SELECT host_ip FROM hosts" -s));
unset IFS;
for i in ${host_ips[@]} ; do echo $i ; done;

to print with key

for i in "${!host_ips[@]}"
do
  echo "key :" $i "value:" ${host_ips[$i]}
done

edited Mar 2, 2016 at 4:20

answered Mar 2, 2016 at 3:35

Santhy K

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Huihoo · Accepted Answer · 2016-03-02 03:26:26Z

0

wspace@lw:~$ echo $host_ips
192.168.1.1 192.168.1.100 192.168.1.101
wspace@lw:~$ arr=($(echo $host_ips))
wspace@lw:~$ echo ${arr[0]}
192.168.1.1
wspace@lw:~$ echo ${arr[1]}
192.168.1.100
wspace@lw:~$ echo ${arr[2]}
192.168.1.101
wspace@lw:~$ echo ${arr[@]}
192.168.1.1 192.168.1.100 192.168.1.101
wspace@lw:~$

maybe this is what you want

answered Mar 2, 2016 at 3:26

Huihoo

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