Redirect output to a bash array - bash

Question

I have a file containing the string
ipAddress=10.78.90.137;10.78.90.149
I'd like to place these two IP addresses in a bash array. To achieve that I tried the following:
n=$(grep -i ipaddress /opt/ipfile | cut -d'=' -f2 | tr ';' ' ')
This results in extracting the values alright but for some reason the size of the array is returned as 1 and I notice that both the values are identified as the first element in the array. That is
echo ${n[0]}
returns
10.78.90.137 10.78.90.149
How do I fix this?
Thanks for the help!

Answer 1

do you really need an array
bash
$ ipAddress="10.78.90.137;10.78.90.149"
$ IFS=";"
$ set -- $ipAddress
$ echo $1
10.78.90.137
$ echo $2
10.78.90.149
$ unset IFS
$ echo $# #this is "array"
if you want to put into array
$ a=( $# )
$ echo ${a[0]}
10.78.90.137
$ echo ${a[1]}
10.78.90.149
#OP, regarding your method: set your IFS to a space
$ IFS=" "
$ n=( $(grep -i ipaddress file | cut -d'=' -f2 | tr ';' ' ' | sed 's/"//g' ) )
$ echo ${n[1]}
10.78.90.149
$ echo ${n[0]}
10.78.90.137
$ unset IFS
Also, there is no need to use so many tools. you can just use awk, or simply the bash shell
#!/bin/bash
declare -a arr
while IFS="=" read -r caption addresses
do
case "$caption" in
ipAddress*)
addresses=${addresses//[\"]/}
arr=( ${arr[#]} ${addresses//;/ } )
esac
done < "file"
echo ${arr[#]}
output
$ more file
foo
bar
ipAddress="10.78.91.138;10.78.90.150;10.77.1.101"
foo1
ipAddress="10.78.90.137;10.78.90.149"
bar1
$./shell.sh
10.78.91.138 10.78.90.150 10.77.1.101 10.78.90.137 10.78.90.149
gawk
$ n=( $(gawk -F"=" '/ipAddress/{gsub(/\"/,"",$2);gsub(/;/," ",$2) ;printf $2" "}' file) )
$ echo ${n[#]}
10.78.91.138 10.78.90.150 10.77.1.101 10.78.90.137 10.78.90.149

Answer 2

This one works:
n=(`grep -i ipaddress filename | cut -d"=" -f2 | tr ';' ' '`)
EDIT: (improved, nestable version as per Dennis)
n=($(grep -i ipaddress filename | cut -d"=" -f2 | tr ';' ' '))

Answer 3

A variation on a theme:
$ line=$(grep -i ipaddress /opt/ipfile)
$ saveIFS="$IFS" # always save it and put it back to be safe
$ IFS="=;"
$ n=($line)
$ IFS="$saveIFS"
$ echo ${n[0]}
ipAddress
$ echo ${n[1]}
10.78.90.137
$ echo ${n[2]}
10.78.90.149
If the file has no other contents, you may not need the grep and you could read in the whole file.
$ saveIFS="$IFS"
$ IFS="=;"
$ n=$(</opt/ipfile)
$ IFS="$saveIFS"

Answer 4

A Perl solution:
n=($(perl -ne 's/ipAddress=(.*);/$1 / && print' filename))
which tests for and removes the unwanted characters in one operation.

Answer 5

You can do this by using IFS in bash.
First read the first line from file.
Seoncd convert that to an array with = as delimeter.
Third convert the value to an array with ; as delimeter.
Thats it !!!
#!/bin/bash
IFS='\n' read -r lstr < "a.txt"
IFS='=' read -r -a lstr_arr <<< $lstr
IFS=';' read -r -a ip_arr <<< ${lstr_arr[1]}
echo ${ip_arr[0]}
echo ${ip_arr[1]}