On 12/18/11 11:45 AM, Stephen Gildea wrote:
> The "read" built-in documentation says,
>
> Exit Status:
> The return code is zero, unless end-of-file is encountered, read times
> out,
> or an invalid file descriptor is supplied as the argument to -u.
>
> I would like to be able to distinguish the no-data conditions. In
> particular I want to know whether I got a timeout or an end-of-file,
> but as you can see, Bash is not documented to behave differently in
> these two cases.
>
> As it happens, in Bash 4.2, "read" exits with status 1 on EOF and
> SIGALRM on timeout. This is just what I want. Can I count on this
> behavior? If so, please commit to it with documentation.
Sure. It seems reasonable that if the read builtin `exits' due to a
signal, it should set the exit status the same way as any other command
that exits that way (128+SIGALRM). The documentation already says
"the exit status is greater than 128 if the timeout is exceeded" in a
couple of places. Does it really need to be in the help text, which is
just a short reminder reference, as well?
Chet
--
``The lyf so short, the craft so long to lerne.'' - Chaucer
``Ars longa, vita brevis'' - Hippocrates
Chet Ramey, ITS, CWRU c...@case.edu http://cnswww.cns.cwru.edu/~chet/
