Tricks for github action workflows

some-workflow-snippet.yaml

# poc of string interpolation in bash / github action

- name: print env variables to job output
  run: for v in `cat env` ; do echo "::set-env name=${v%%=*}::${v##*=}" ; done


- name: use (maybe ) in shell command
  run: docker push myrepo/myapp:${TAG_REF#refs/tags/}
  env:
    TAG_REF: ${{ github.ref }}
    
# references:
# - shell string interpolation https://pubs.opengroup.org/onlinepubs/009695399/utilities/xcu_chap02.html
# - action workflow syntax: https://help.github.com/en/actions/reference/workflow-syntax-for-github-actions
# - action expression/function syntax: https://help.github.com/en/actions/reference/context-and-expression-syntax-for-github-actions