Re: posix command search and execution

[Mike Jonkmans]

On Tue, Nov 07, 2023 at 11:49:25AM -0500, Chet Ramey wrote:
> On 11/7/23 8:54 AM, Mike Jonkmans wrote:

...

> > > Look at https://www.austingroupbugs.net/view.php?id=854 for a discussion
> > > of this issue.
> > Thanks for the link, I find that very hard to read though.
> It's also incomplete; there was a lot of discussion on the mailing list.
> I don't have a link to a usable public mailing list archive.

So the discussion is hidden. Hmm.
I already did not find it much of a discussion in terms of opposition.

...

> > Then again, is there a requirement for the standard utilities to be
> > found in the current PATH? Or do they just need to be present somewhere.
> They have to be findable using the value returned by `getconf PATH'. If
> the user modifies PATH to, say, prepend directories before that standard
> PATH, then all bets are off.

I see. Weirdly on Ubuntu 22.04, with /bin symlinked to /usr/bin,
`getconf PATH' produces `/bin:/usr/bin'.
That looks like a recipe for redundant `stats'.

> > > > - The 'newgrp' utility (mentioned in 1d) is not a builtin in bash.
> It's gone in the latest draft of the next version of the standard anyway.

Good riddance.

> > > > - Utilities:
> > > >     https://pubs.opengroup.org/onlinepubs/9699919799/idx/utilities.html
> > > >     Q: Where is `standard utilities' defined - as used in 1d.
> > > These are the standard utilities.
> > Some of these utilities are marked with optional `codes'.
> > Are these also considered standard utilities - even when the option is
> > not true?
> Not really, no. If the implementation claims to support, for instance, XSI,
> the XSI-shaded utilities have to be present and they have to behave as
> specified. If the implementation doesn't, they don't.
> https://pubs.opengroup.org/onlinepubs/9699919799/basedefs/V1_chap02.html#tag_02_01_04
> 
> So in 1d, if the system doesn't claim XSI conformance, the shell doesn't
> have to include type or ulimit in this required invocation order.


> (But wait! The list of intrinsics in the latest draft includes type and
> ulimit, and isn't XSI-shaded. So that will change.)

Isn't that described in `Note 0004803' in 
https://www.austingroupbugs.net/view.php?id=854
(not possible to add shade to type and ulimit in column order)

-- 
Regards, Mike Jonkmans