on: push
env:
  MY_SHELL: sh
jobs:
  check:
    runs-on: ubuntu-latest
    defaults:
      run:
        shell: ${{ env.MY_SHELL }}
    steps:
      - shell: ${{ env.MY_SHELL }}
        run: |
          if [ -z ${BASH+x} ]; then
            echo "I'm sh!"
          else
            exit 1
          fi
      - run: |
          if [ -z ${BASH+x} ]; then
            echo "I'm sh!"
          else
            exit 1
          fi
  check-container:
    runs-on: ubuntu-latest
    container: alpine:latest
    steps:
      - shell: ${{ env.MY_SHELL }}
        run: |
          if [ -z ${BASH+x} ]; then
            echo "I'm sh!"
          else
            exit 1
          fi