Expose environment variables in CircleCI run step

Reference

https://circleci.com/docs/2.0/env-vars/

Another possible method to interpolate values into your config is to use a run step to export environment variables to BASH_ENV, as shown below.

steps:
  - run:
      name: Setup Environment Variables
      command: |
        echo "export PATH=$GOPATH/bin:$PATH" >> $BASH_ENV
        echo "export GIT_SHA1=$CIRCLE_SHA1" >> $BASH_ENV

In every step, CircleCI uses bash to source BASH_ENV. This means that BASH_ENV is automatically loaded and run, allowing you to use interpolation and share environment variables across run steps.

Note: The $BASH_ENV workaround only works with bash. Other shells probably won’t work.