CODEWITHSUNDEEP
bashshell
sattu
sattu

Reputation: 648

Retrieving value of a variable in shell

I have following scenario.

#!/bin/bash
export avalue_name="stack"
LOOPERS=${LOOPERS:-avalue}
for LOOPER in $(echo "$LOOPERS" | tr ',' "\n")
do
   actualVar="$LOOPER""_name"
   echo "actualVar - $actualVar"
done

Output is

actualVar - avalue_name

I want the output to be 

actualVar - stack

How would I do it?

I tried $($LOOPER_name). It doesn't work either.

Upvotes: 2

Views: 216

Answers (1)

heemayl
heemayl

Reputation: 42137

Two approaches:

Use an intermediate variable, and use shell indirect reference on that:

$ avalue_name="stack"

$ LOOPER=avalue

$ temp="${LOOPER}_name"

$ echo "${!temp}"
stack

Or use eval, not recommended:

$ eval echo "\$${LOOPER}_name"
stack

Points:

  • _ is a valid variable constituent character, so while referring a variable you need to enclose it with {} when another valid variable constituent character is immediately before or after it

  • unless absolutely necessary, do not use all uppercases for user-defined variables to prevent possible mix-up with the environment variables

Upvotes: 3

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