I think this is a topic that every Linux user eventually stumbles into. It is indeed quite frustrating.

I found the article hard to follow, but maybe because I was already familiar with the problem and was just skimming. Skip to "Some experiments..." for the actual useful examples.

I disagree with the conclusion, though. I think there should just be more obvious ways to escape the input so one can keep their sanity with nested 'sh -c' invocation. Maybe '${var@Q}' and print '%q' are enough (can't believe I didn't know those existed!)