Get Environment Variable from Docker Container

bash docker environment-variables

The proper way to run echo "$ENV_VAR" inside the container so that the variable substitution happens in the container is:

docker exec <container_id> bash -c 'echo "$ENV_VAR"'

bash docker environment-variables

To view all env variables:

docker exec container env

To get one:

docker exec container env | grep VARIABLE | cut -d'=' -f2

bash docker environment-variables

You can use printenv VARIABLE instead of /bin/bash -c 'echo $VARIABLE. It's much simpler and it does not perform substitution:

docker exec container printenv VARIABLE

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