Re: Should [[ -v 1 ]] be supported?

[Peng Yu]

> You're whacking moles.  Use a profiler.  That's what they're for.

I've already shown that $() is a major problem to slow down the speed
and I have reduced using its usage in my code and significantly
improved the performance. Nevertheless, it doesn't mean that it is not
necessary to systematically evaluating features that are used
frequently.

> Yes, I can.  You need to identify where bash is _actually_ spending most
> of its execution time, and a profiler can help you do that.

Yes and no. For a particular bash script, you can quantify which bash
features are the most time-consuming. But you can not profile all the
bash scripts that have ever been written. Since there are only limited
features in bash, in this case, a logical way to go is to at least
profile each commonly used feature with minimal code (as just for and
repetitive calling that features as I do) and understand its pros and
cons. A profiler is an overkill in this case.

-- 
Regards,
Peng