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

[Martijn Dekker]

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.

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