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Re: Leak in BASH "named" file descriptors?

From: Chet Ramey
Subject: Re: Leak in BASH "named" file descriptors?
Date: Wed, 13 Apr 2016 14:08:27 -0400
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On 4/13/16 9:34 AM, Pierre Gaston wrote:

> For me the value is in 1) not hard coding the number and 2) being able to
> use more explicit names (eg "logfile" rather than "3"), nothing more.

If you limit the effects to those two, it's not a compelling feature to
add.  In practice, the first is not a big problem if you're careful, and
the second can be trivially emulated with a single assignment statement.

> Of course if you use {var} for the redirections of an external command it's
> useless but not using a hard coded number can be useful if you use
> functions and don't want to have conflicts with someone else's function.

This is true, though bash does save and restore file descriptors where it
can if your hard-coded number is already in use.

> I don't really understand why using a symbolic name would need to provide
> more control, and in my opinion  {var}> doesn't really provide something
> you can't do otherwise regarding the handling of the fd, it just has a
> different behavior.

It's an opportunity to provide more flexible behavior.  The standard ways
to use file descriptors still exist, so if you don't like the different
behavior you have options.

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

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