Bash help requested: Capturing command errors within pipes

[Daniel B. Thurman]

S P Arif Sahari Wibowo wrote:
> On Thu, 19 Mar 2009, Daniel B. Thurman wrote:
>> How could one go about capturing command errors within pipes?
>
> The variable $PIPESTATUS is just for that.
>
I tried it, seems not to work.

Try capturing a sed error when re1 or re2 has a bad regular
expression string.  I have not been able to catch the error.