gitattributes - how to identify bash script files with no extension

I'm just getting up to speed with using git. I've been using the examples in https://github.com/Danimoth/gitattributes to put together a gitattributes file for my various projects (mostly bash and python scripts). My problem is that most of my bash scripts have no file extension. Is there a pattern I can use to explicitly select these (e.g. for a filter)? Or would it be easier to rename them with an .sh extension?