CODEWITHSUNDEEP
shell
user3436906
user3436906

Reputation: 45

how to assign one variable value into another variable in shell script

I tried below shell code to get the value of temp as "good 1" and "good 2", but I was not able to.

hello_1="good 1"
hello_2="good 2"
for i in 1 2
do
temp="hello_$i"
echo $temp
done

I want to fetch hello_1 and hello_2 variables value into temp variable. I tried above script but I was not able to get values of hello_1 and hello_2 into temp. please help me.

Upvotes: 4

Views: 8609

Answers (1)

shellter
shellter

Reputation: 37318

If you using bash 4 or higher, read about indirect references. But to answer your question you can do

hello_1="good 1"
hello_2="good 2"
for i in 1 2
do
    eval temp="\$hello_$i"
    echo $temp
done

output

good 1
good 2

eval is usually considered evil in shell programming. Don't get in a habit of using it.

The key technique is that the eval provides a 2nd evaluation of the line. On the first pass it looks like

 eval temp="$hello_1"

Note how the $i is displayed as 1, AND that the leading \\ char is removed from \$hello_1, so when the eval is executed the processing of the line takes the value of $hello_1 variable and assigns it to temp, i.e.

 temp="good 1"

IHTH

Upvotes: 4

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