Create new bash process with altered environment variables from inside script and execute command with new environment [duplicate]

Question

I have a bash script which sets environment variables and then creates another (child?) bash process in which those variables are set.

I'd like to execute a command inside that new bash script, which is within the scope of the newly created environment variables. I know that I can call bash and pass in another existing .sh file, however I need to pass in a string which can be dynamically generated.

Is this possible?

#!/bin/bash
# ....
export AWS_ACCESS_KEY_ID=$AccessKeyId
export AWS_SECRET_ACCESS_KEY=$SecretAcessKey
# ...

# This line fails
bash  <$(echo "aws sts get-caller-identity")

Thanks very much.

Does this answer your question? How to execute new bash command inside shell script file? — Deepan
– Deepan, Commented Aug 14, 2022 at 13:44
no, not really. That is executing commands in another file. I want to specify what to execute via a string which can be generated from previous steps in the script. I'll reword the question. — Damien Sawyer
– Damien Sawyer, Commented Aug 15, 2022 at 1:47

metzkorn · Accepted Answer · 2022-08-15 02:10:04Z

1

You can use a here document to accomplish this effect.

#!/bin/bash
export ENV_VAR="hello"
# some dynamically made script that uses the environment variable 
dynamic_script="echo \$ENV_VAR" 

# notice if you were to echo this here, it would have the dollar sign
# echo $dynamic_script

bash<<HERE
$dynamic_script
HERE

Documentation: https://tldp.org/LDP/abs/html/here-docs.html

Though I don't see why you couldn't simply output the script to a file and run that.

echo "$dynamic_script" > my_child.sh
chmod +x my_child.sh
./my_child.sh

answered Aug 15, 2022 at 2:10

metzkorn

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2 Comments

Damien Sawyer Over a year ago

Thank you - that's perfect. I guess that I could just write a file, but don't you find it cleaner not to? Why write a temp file when you don't need to?

metzkorn Over a year ago

That's true. I can understand the appeal of wanting everything contained.

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