Re: Portability problems of "Usual Tools" not described in manual

[Ralf Wildenhues]

Hello,

* Eric Blake wrote on Tue, Mar 17, 2009 at 03:43:32PM CET:
> According to Russ Allbery on 3/12/2009 10:32 PM:
> > 2. On HP-UX 11.23, regexp matching with expr does not allow multiple sub-
> >    expressions:
> > 
> >      bash-3.1$ expr 'Xfoo' : 'X\(f\(oo\)*\)$'
> >      expr: More than one '\(' was used.

(BTW, I can verify this.)

> Ouch.  I don't have access to HP-UX to verify, but this means we need to
> audit autoconf source to make sure we don't violate this restriction.

There are no such instances in Autoconf, Automake, Libtool, gnulib.
I checked; but also, they would have shown up on our radar before.

> > 3. On GNU/Linux the regexp "$", when used with older versions of expr,
> >    matches newlines embedded in the match string:
> > 
> >      bash-3.1$ baz='foo
> >      > bar'
> >      bash-3.1$ expr "X$baz" : 'X\(foo\)$' || echo baz
> >      foo
> 
> I'm assuming this was from an older version of coreutils?  Can someone
> determine 'expr --version' in the broken case, to see when it was fixed?

I see one instance of this, in the 'dirname' emulation code in m4sh
(also in install-sh).  Luckily, coreutils dirname works, so that isn't
a problem.

Cheers,
Ralf