* [Shellcheck][2] is a wonderful tool to *detect*, and give general advice, about brittle bash code. The only thing missing is something to say yes with, and *apply* those advice (assuming proper review of course).
* I asked [this SO question][3], for a tool that could rewrite bash scripts with proper quoting. One answerer beat me to it. But if it was me, I would do a syntax highlighter in the same tool (as a way to see if the parser gets lost, and make the most out of the parser, because bash is like quantum mechanics – nobody really knows how it works).
For those allergic to building from source, a few precompiled binaries are also available in the [releases](https://github.com/anordal/shellharden/releases).
Don't apply `--transform` blindly; code review is still necessary: A script that *relies* on unquoted behavior (implicit word splitting and glob expansion from variables and command substitutions) to work as intended will do none of that after getting the `--transform` treatment!
In that unlucky case, ask yourself whether the script has any business in doing that. All too often, it's just a product of classical shellscripting, and would be better off rewritten, such as by using arrays. Even in the opposite case, say the business logic involves word splitting; that can still be done without invoking globbing. In short: There is always a better way than the forbidden syntax (if not more explicit), but some times, a human must step in to rewrite. See how, in the accompanying [how to do things safely in bash](how_to_do_things_safely_in_bash.md).
