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Re: Conditional operator in Shell Arithmetic section


From: uzibalqa
Subject: Re: Conditional operator in Shell Arithmetic section
Date: Sun, 19 Mar 2023 14:40:26 +0000

------- Original Message -------
On Monday, March 20th, 2023 at 2:18 AM, Kerin Millar <kfm@plushkava.net> wrote:


> On Sun, 19 Mar 2023 13:17:14 +0000
> uzibalqa uzibalqa@proton.me wrote:
> 
> > ------- Original Message -------
> > On Sunday, March 19th, 2023 at 10:56 AM, uzibalqa uzibalqa@proton.me wrote:
> > 
> > > ------- Original Message -------
> > > On Sunday, March 19th, 2023 at 10:25 AM, Lawrence Velázquez vq@larryv.me 
> > > wrote:
> > > 
> > > > You can find such material elsewhere. Any decent C teaching material
> > > > can tell you how ? : works and how you might use it in practice. The
> > > > official bash manual is not the only place to learn about such things
> > > > (although finding good third-party material is admittedly fraught).
> > 
> > What changes, additions, clarifications and improvements would you suggest 
> > and do?
> 
> 
> The POSIX documentation states, "The evaluation of arithmetic expressions 
> shall be equivalent to that described in Section 6.5, Expressions, of the ISO 
> C standard." [] By contrast, the bash manual states, "The operators and their 
> precedence, associativity, and values are the same as in the C language." The 
> latter wording strikes me as being more digestible by its overall audience. 
> On the other hand, the POSIX wording makes it rather more clear as to what to 
> look for, and where to look within upon finding it, so there may yet be some 
> room for improvement there. Further, the SEE ALSO section does not (directly) 
> acknowledge the existence of "Shell Command Language" and "ISO/IEC 9899:2018" 
> (C) in their capacity as distinct specifications. Perhaps it should.
> 
> Otherwise, I'm not sure that there is much else to be done. The operator can 
> be trivially searched for in a typical man pager e.g. by using \?.: as a 
> pattern. Perhaps something could be done to make GNU info(1) more easily 
> match the relevant section upon searching its index. However, in my 
> experience, the majority of capable bash users act as though info doesn't 
> exist, while newcomers struggle to use a pager effectively, let alone info. 
> Introducing it as the "conditional (ternary) operator" might help some 
> people, though it should be borne in mind that it is correctly referred to as 
> the "conditional operator", irrespective of its provenance in languages other 
> than sh and C.

We could see how to improve info so newcomers would likely use it. 
I see no benefit in putting time and effort on info when nobody would use it.  
I do use info as it is quicker getting information and examples from the 
terminal.  One problem that occurs to me is that in bash I cannot call info to 
see for some examples.  Whereas fol awk, sed, grep, find, I can see many 
helpful examples.

As to your comment last, instead of introducing it as "conditional (ternary) 
operator", we could still stay with "conditional operator" but with a side note 
later on mentioning that it has been called  "conditional ternary operator" in 
sh and C.  That way a search for "ternary" would get you to the right section.

> [*] 
> https://pubs.opengroup.org/onlinepubs/9699919799/utilities/V3_chap01.html#tagtcjh_15
> 
> --
> Kerin Millar



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