Re: How to test if a variable is declared?

[Peng Yu]

Hi Chet, Is adding a switch -q to `declare` to suppress the output of
`declare -p` or adding a switch to [[ be an option to allow testing
whether a variable declare?

On 3/13/20, Peng Yu <pengyu.ut@gmail.com> wrote:
> On Fri, Mar 13, 2020 at 9:25 AM John McKown <john.archie.mckown@gmail.com>
> wrote:
>
>> On Fri, Mar 13, 2020 at 9:01 AM Peng Yu <pengyu.ut@gmail.com> wrote:
>>
>>> I am trying to use bash efficiently. I am not saying that I have seen
>>> CPU
>>> as a concern in a real application. But I want to avoid the
>>> do-something-then-discard-it approach as much as possible. Sometimes, a
>>> solution can be found in bash. Sometimes, it can’t be done as in this
>>> case
>>> at this moment. Either way is fine with me. But I need to know where the
>>> limit is of bash.
>>>
>>> For this specific case, I don’t think that bash could not support it.
>>> After
>>> all, it could be supported for example by adding a new switch to [[.
>>>
>>
>> Or maybe a "-q" (for quiet) or "-s" (for silent) as a "suboption" for
>> declare -p (declare -pq variable) so that it only sets $?
>>
>
> That also could be a possibility.
>
>
>>
>>
>>>
>>>
>>> Peng
>>
>>
>>>
>>
>> --
>> People in sleeping bags are the soft tacos of the bear world.
>> Maranatha! <><
>> John McKown
>>
> --
> Regards,
> Peng
>


-- 
Regards,
Peng