Variable substitution in Shell script

Question

I have declared one variable IS_abc=false , on basis of certain condition I am changing value to IS_abc=true

IS_abc=false
declare -a my_arr
my_arr = ('abc' 'pqr' 'xyz')
....
.... // some operation
IS_abc=true
for i in "${my_arr[@]}"
do
    //here i want to access value of $IS_abc  as true
    //how to do this
done

I have tried accessing using $IS_'$i' , but it raising error as invalid substitution

Tell me if I am doing anything wrong here?

Answer 1

You can use indirect var reference:

my_arr=('abc' 'pqr' 'xyz')
IS_abc=true

var="IS_${my_arr[0]}"
echo "${!var}"

Output:

true

Answer 2

I'm doing it like this:

value=`eval echo \\${IS_${i}}`

There's probably a better way but this should work.