One way I force people (mostly myself) to include shebang lines: Have a scripts directory in my repo that mixes shell and python scripts with no file extension

One way I force people (mostly myself) to include shebang lines: Have a scripts directory in my repo that mixes shell and python scripts with no file extensions and executable bits set. If I don't put a shebang, it just doesn't run. Of course, this requires you to have firm control of code style policies.