Thank you for this. About a year ago I came across ShellCheck thanks to a comment just like this on Reddit. I also happened to be getting towards the end of a project which included hundreds of lines of shell scripts across dozens of files.

It turns out that despite my workplace having done quite a bit of shell scripting for previous projects, no one had heard about Shell Check. We had been using similar analysis tools for other languages but nothing for shell scripts. As you say, it turned up a huge number of errors, including some pretty spicy ones when we first started using it. It was genuinely surprising to see how many unique and terrible ways the scripts could have failed.