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Re: How to use PROMPT_COMMAND(S) without breaking other scripts

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From Martijn Dekker <martijn@inlv.org>
Newsgroups gnu.bash.bug
Subject Re: How to use PROMPT_COMMAND(S) without breaking other scripts
Date Mon, 24 Aug 2020 20:53:43 +0100
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Op 24-08-20 om 20:37 schreef Chet Ramey:
> On 8/24/20 12:58 PM, Martijn Dekker wrote:
>> Op 24-08-20 om 15:57 schreef Chet Ramey:
>>> I sometimes think I should have stuck with converting PROMPT_COMMAND to
>>> an array. Either way, there's going to be a transition, and maybe that
>>> would have been the easiest.
>>
>> Is it too late? I think that would actually be cleaner than adding a
>> separate array, per Koichi's report.
> 
> We're not "adding" anything. Bash just looks for this variable and reacts
> if it finds it. It's not a special variable, and bash doesn't create it if
> it doesn't exist.


So now you're adding code that looks for an array. Which is something 
other than nothing.

Granted, my language wasn't very precise, but I'm fairly confident that 
my intent was understandable.

> What I mean is looking for PROMPT_COMMAND as happens now, and reacting a
> different way if it's an array variable. That would resolve the existing
> assignment issues, but open up the separate issues you describe.


But I also suggested a way of avoiding those issues: initialise 
$PROMPT_COMMAND a.k.a. ${PROMPT_COMMAND[0]} as empty.

- M.

-- 
||	modernish -- harness the shell
||	https://github.com/modernish/modernish
||
||	KornShell lives!
||	https://github.com/ksh93/ksh

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Re: How to use PROMPT_COMMAND(S) without breaking other scripts Martijn Dekker <martijn@inlv.org> - 2020-08-24 20:53 +0100

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