Re: updating shopt compat settings to include current version

[Chet Ramey]

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On 10/20/15 2:49 PM, Mike Frysinger wrote:

>>>> I mean, in theory, it's simple to do that:
>>>>
>>>> unset BASH_COMPAT
>>>> shopt -u compat31
>>>> command shopt -s compat32 2>/dev/null
>>>
>>> ... but that doesn't work in bash-3.2:
>>> $ bash-3.2 -c 'shopt -s compat32'
>>> bash-3.2: line 0: shopt: compat32: invalid shell option name
>>
>> No, it really does.  That's why I redirected the output to /dev/null.  I
f
>> you run with `set -e' enabled, you can follow it with `|| :'.
>>
>> Running those commands leaves shell_compatibility_level == 32 on all
>> existing versions of bash >= bash-3.2.   The trick is that on bash-3.2,
>> unsetting compat31 sets the shell compatibility level to 32, so the
>> failed attempt to set compat32 doesn't make a difference.
> 
> my point was to have a code snippet that works for any bash version and a
> shifting base.  we've established that you aren't interested in adding mo
re
> compat flags, and that BASH_COMPAT is not useful for error checking.  fin
e,
> we'll just add some ad-hoc checks ourselves using the existing bash versi
on
> variables.  that isn't supposed to sound petulant, just accepting of the
> reality of the situation.

I don't think you're petulant.  I gave you the code snippet you wanted.
You can use whatever you'd like.

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