Improvements for ksh and zsh

[mcandre]

bashate appears to lack parsing for non-bash languages such as ksh and zsh.

One option is for bashate to add parsing support for these common sh implementations. Many of bashate's useful warnings would apply to ksh and zsh scripts.

Meanwhile, bashate unfortunately presents some spurious errors when linting large projects that feature a mixture of (POSIX) sh, explicit bash scripts, and ksh/zsh scripts. Unless bashate adds support for alternative interpreters like ksh* (it's a family), kmksh, pdksh, and zsh, it would be helpful to automatically skip these files, and their associated user configuration filenames. Doing so removes noise when linting large projects with bashate.

As a workaround, I am using a personal utility to detect all shell script files, and filter out those associated with unsupported interpreters.

https://github.com/mcandre/stank

Example:

$ stank -exInterp 'zsh' | xargs -n 1 bashate -i E006