github.com/nektos/act@v0.2.63/pkg/runner/testdata/shells/defaults/push.yml (about)

     1  on: push
     2  jobs:
     3    check: # GHA uses `bash` as default for runners
     4      runs-on: ubuntu-latest
     5      steps:
     6        - run: |
     7            if [[ -n "$BASH" ]]; then
     8              echo "I'm $BASH!"
     9            else
    10              exit 1
    11            fi
    12    check-container: # GHA uses `sh` as default for containers
    13      runs-on: ubuntu-latest
    14      container: alpine:latest
    15      steps:
    16        - run: |
    17            if [ -z ${BASH+x} ]; then
    18              echo "I'm sh!"
    19            else
    20              exit 1
    21            fi