yasnippet and general shebang

[andrea]

I'm using a lot yasnippet and it's really great.
Now for example I would like to make
! a general shebang snippet
I've done it already for example for python
--8<---------------cut here---------------start------------->8---
# -*- mode: snippet -*-
# name: bang
# key: !
# --
#!/usr/bin/env python
$0
--8<---------------cut here---------------end--------------->8---

how can I make it more general?
Should I just put in the root directory and it's valid for all modes?

I think just using #!/usr/bin/env <major-mode - "mode">
would be fine in, right?