on: push
jobs:
  check: # GHA uses `bash` as default for runners
    runs-on: ubuntu-latest
    steps:
      - run: |
          if [[ -n "$BASH" ]]; then
            echo "I'm $BASH!"
          else
            exit 1
          fi
  check-container: # GHA uses `sh` as default for containers
    runs-on: ubuntu-latest
    container: alpine:latest
    steps:
      - run: |
          if [ -z ${BASH+x} ]; then
            echo "I'm sh!"
          else
            exit 1
          fi
