Re: [doc] LINES/COLUMNS auto-update in non-interactive shells contradicts manual

Chet Ramey <[email protected]> Mon, 11 May 2026 11:47:15 -0400

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

On 5/10/26 5:10 PM, Zachary Santer wrote:

> In fact, they're currently set in a noninteractive shell after any
> external command runs, if checkwinsize is enabled.

The description of checkwinsize already says this, and did in bash-5.1.

> They may as well be made to work the same in a noninteractive shell as
> they do in an interactive one.

Interactive shells handle SIGWINCH for the benefit of readline(), since
that's what people expect. There is less reason to do that in a non-
interactive shell.

>>> Why not just set the values of LINES and COLUMNS when the
>>> script begins to run,
>>
>> Because users expect the shell to honor the values they pass in the
>> environment.

It's easy to do

shopt -u checkwinsize
: ${LINES:=24} ${COLUMNS:=80}

if it matters, without having to wait for any changes to the shell. TheOP 
is already two major versions back.

-- 
``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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