Using env var in GitHub Actions

Define REACT_APP_GOOGLE_MAPS_API_KEY with value 1@3$ in Repo Settings -> Secrets -> New repository secret: https://github.com/photo-map/photo-map.github.io/settings/secrets/actions

.github/workflows/save_env_var_to_file.yml

name: save_env_var_to_file
on: push
env:
  REACT_APP_GOOGLE_MAPS_API_KEY: $
jobs:
  test:
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v1
      - name: chmod
        run: chmod 777 ./save_env_var_to_file.sh
      - name: Save env var to file
        run: ./save_env_var_to_file.sh
      - name: Upload build/output.txt
        uses: actions/upload-artifact@v2
        with:
          name: output
          path: ./build

save_env_var_to_file.sh

#!/bin/bash
echo echo_env start
echo $REACT_APP_GOOGLE_MAPS_API_KEY # this will print *** in GitHub Action console
mkdir ./build
echo $REACT_APP_GOOGLE_MAPS_API_KEY > ./build/output.txt
echo echo_env end

After workflow is done, you could download the artifact, and find the output.txt content is 1@3$.

See https://github.com/xx7y7xx/github-actions-demo/blob/main/.github/workflows/echo_env.yml