Shellcheck looks to the shebang statement at the beginning of a shell script as one means of determining what language is used. This works well for shell scripts that are meant to be called as an executable.

However, there are non-executable shell files where the convention is to not include the shebang statement in the file because they are meant to be sourced either by the shell during startup (e.g., bashrc) or because they are part of a shell library.

These files would benefit from spellcheck but can't be used as they are without including a shebang statement.

I'd like to propose a directive for this specific case that can specify the language. Something like:

# shellcheck lang=bash

There are other related issues that have brought up this issue but the suggestions were to fall back to sh #215 or ignore the issue #237. I think it'd be best to allow your users the ability to specify the language type to take advantage of language specific features.

I recognize that shellcheck -s dialect exists but this doesn't help in the case of vim's syntastic plugin.

Finally, the lang directive should throw a warning if a shebang is used simultaneously.

Alternatively, the shebang statement could simply be added to these files but I hesitate here because this is not the convention for source files.

Thoughts?