For the record, I am personally usually a fan of making exceptional conditions return values (though I prefer Rust's explicit unwrapping to Go's approach), since in most programs it's good to think at least somewhat carefully about error handling anyway. However, in one-liners, there is no need for proper error handling, and the vast majority of exceptional conditions (e.g. file not found) are caused by mistakes that should be rectified by changing the code. Therefore, in a language that prioritizes one-liners, as I believe any shell should, I believe the traditional exception approach is the best.