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Accepted
Santosh Hegde
Asked: 2017-02-03 10:08:41 +0800 CST

How to generate environment variable name dynamically and export it

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I want to generate environment variable name dynamically and set the value to that variable. I wrote a shell script as below.

temp="$(date +%s)"
echo $temp
export ${temp} = "Test value"
echo "Pass variable ${temp}"

In the above code, generated timestamp should be the key and "Test value" is the value for that key. This key and value have to export to the session.

How can I achieve this using shell script?

command-line

1 Answers

  1. Best Answer

    You could use printf -v to create variables dynamically, for example:

    temp=somename
echo $temp
printf -v $temp "Test value"
echo $somename

    This will output "Test value".

    Note that temp="$(date +%s)" won't work, because the output of $(date +%s) is numeric, and variable names in Bash cannot start with a number. You would have to give it a non-numeric prefix, for example:

    temp="t$(date +%s)"

    To export the variable, you can simply do:

    export $temp

    Here's a complete example, with proof that the variable really gets exported in the environment:

    temp=t$(date +%s)
echo $temp
printf -v $temp "Test value"
export $temp
sh -c "echo \$$temp"

    Outputs for example:

    t1486060416
Test value
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