Re: [PATCH] rev: fix some issues

Chet Ramey <[email protected]> Fri, 8 May 2026 09:09:02 -0400

Newsgroups	gmane.comp.shells.bash.bugs
Organization	ITS, Case Western Reserve University
Message-ID	<[email protected]>

On 5/7/26 4:55 PM, Duncan Roe wrote:

> The original code is correct. The effect of including this patch is that rev
> with no arguments is a no-op. rev with no arguments *should* read lines from
> standard input (fd 0).

You're both right. If fd 0 is closed for some reason when `rev' is invoked
with a filename argument, the open() will return file descriptor 0 and the
original code will leave it open. Since it's a builtin, the open file
descriptor will persist in the shell execution environment.

The usual fix is to use a flag that tells whether the file descriptor is
the inherited stdin or the result of open(). I added that yesterday.

Chet

-- 
``The lyf so short, the craft so long to lerne.'' - Chaucer
		 ``Ars longa, vita brevis'' - Hippocrates
Chet Ramey, UTech, CWRU    [email protected]    http://tiswww.cwru.edu/~chet/

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