When you have a multi-line value, snakeyaml (as least how I have it configured) doesn't seem to dump things properly. We want:

• kind: !shell
  command: |
  #!/bin/bash -e
  ...

However, the value it simply dumped regardless of the existence of new lines as:

• kind: !shell
  command: #!/bin/bash -e
  ...

Which won't parse properly.