Does error handling in your bash scripts ever become annoying enough to warrant a rewrite in, say, OCaml?
Regardless, I'd actually prefer Haskell's do-notation for both asynchronous commands and shell-scripting tasks. Even though Haskell isn't my favorite language, do-notation is quite nice for this.
But we don't do it often. Each language has its strengths and weaknesses, and the constraints of a small script tend not to change that much over time. The script either starts other executables and pipes some text around, or it does some computation. The choice of which to use is often (but not always) clear.
That said, there are still little things we use Bash for. But our tolerance for large bash scripts has diminished greatly over the years.
ocaml isn't that far off, just even less popular...