Re: [gentoo-dev] POSIX shell and "portable"

[Michael Haubenwallner]

On Mon, 2007-11-05 at 10:13 +0000, Roy Marples wrote:
> While I still have access to the u@g.o email, I'll respond here.
>
>
> On Mon, 2007-11-05 at 10:22 +0100, Michael Haubenwallner wrote:
> > On Sat, 2007-11-03 at 00:47 +0000, Roy Marples wrote:
> >
> > As it seems too few people really accept your suggestion, I feel it's
> > time for me to chime in too, although I don't know what exactly POSIX-sh
> > standard defines.
>
> > Agreed, but (speaking for alt/prefix):
> >
> > Alt/prefix is designed to (mainly) work without superuser access on the
> > target machine, which may also be Solaris, AIX, HP-UX and the like.
> > /bin/sh on such a machine is not POSIX-shell, but old bourne-shell
> > (unfortunately with bugs often).
> > And it is _impossible_ to have sysadmins to get /bin/sh a POSIX-Shell
> > nor to have that bugs fixed.
> >
> > But yes, on most machines there is /bin/ksh, which IMHO is POSIX
> > compliant (maybe also with non-fixable bugs).
> >
> > Although I do not know yet for which _installed_ scripts it'd be really
> > useful to have them non-bash in alt/prefix, I appreciate the discussion.
> >
> > To see benefits for alt/prefix too, it _might_ require that discussion
> > going from requiring /bin/sh being POSIX-sh towards being
> > bourne-shell...
>
> Actually you missed the mark completely.
> Nothing in the tree itself specifies what shell to use - instead it's
> the package manager. So the PM on Gentoo/Linux/FreeBSD *could*
> be /bin/sh and on the systems where /bin/sh is not possible to change to
> a POSIX compliant shell then it can still use /bin/bash or wherever it's
> installed.

So "have the installed scripts to not require bash" is another topic ?

Ok then:
Given that we want to have the tree "more generic unix-able":
What is the benefit from having the tree being POSIX- but not
bourne-shell compatible, so one still needs bash on Solaris/AIX/HP-UX ?
Because I'd say those three are the biggest substitutes for "unix",
while I'd call *BSD and Linux just "unix derivates" (although with
enhancements)...

>
> This also applies to the userland tools. If the ebuild or eclass *has*
> to use the GNU variants then it should either adjust $PATH so that it
> finds them first, or it prefixes them all with g, like it does on
> Gentoo/FreeBSD.
>
> None of this is technically challenging in itself, it's just that the
> key people who would have to do the work to make this possible have
> already given a flat out no.

In the early prefix days I had some portage enhancement, providing a
wrapper-function around all coreutils/findutils/diffutils/grep/others,
trying to find a GNU implementation for them. And if not found, try to
map some args to the native ones ("xargs -r" fex - although didn't work
as shell-function).
But then we decided to always provide USERLAND=GNU in prefix and this
portage patch was thrown away.

>
> > > > It seems to me that you actually mean "more FreeBSD-able" or something,
> > > > which is a high price to pay for a relatively small part of Gentoo as a
> > > > whole.
> > >
> > > More embeddable.
> > > More BSDable.
> > > More Linuxable - bash isn't the only linux shell, there are plently of
> > > others.
> >
> > More (generic) unix-able.
>
> Exactly so :)

Not really as long as not being bourne shell compatible like autoconf's
configure. I won't trust to have a POSIX shell like /bin/ksh everywhere,
but /bin/sh only, which usually is just a bourne shell on "unix".

/haubi/
-- 
Michael Haubenwallner
Gentoo on a different level

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