Re: poor <&- behavior under ulimit -n

[Chet Ramey]

On 10/27/10 6:25 PM, Eric Blake wrote:

> Description:
> Bash does not behave well when under artificial fd pressure due to
> ulimit -n.  It issues a spurious warning to stderr because it tries
> to save necessary fds starting at 10.  Compare this with ksh93, which
> saves fds starting at 3.
> 
> Many other shells (for example, dash or BSD /bin/sh) exit with
> non-zero status if they can't use fd 10, rather than proceeding onwards.
> At any rate, bash MUST exit with failure if it cannot save an fd, even
> if you decide that it is unsafe to copy ksh93's action of saving at fd
> 3 rather than 10.  

That's not actually true.  What bash must do is to throw a redirection
error, which has specific Posix-defined consequences in a non-interactive
shell, which differ between special builtins and other utilities.

Chet
-- 
``The lyf so short, the craft so long to lerne.'' - Chaucer
                 ``Ars longa, vita brevis'' - Hippocrates
Chet Ramey, ITS, CWRU    chet@case.edu    http://cnswww.cns.cwru.edu/~chet/