GitHub Actions check branch

GitHub Actions workflow that checks if branch is master before running job master-check:

# .github/workflows/check.yml
on: push
jobs:
  master-check:
    if: github.ref == 'refs/heads/master'
    runs-on: ubuntu-latest
    steps:
      - run: echo "Running on branch $GITHUB_REF"

The if conditional checks that the branch is master:

if: github.ref == 'refs/heads/master'

To skip the master branch, use the != operator:

if: github.ref != 'refs/heads/master'

See GitHub Actions documentation example.