Re: sed vs. gsed

[Mike Miller]

On Mon, Sep 19, 2016 at 16:29:46 -0700, Rik wrote:
> The autoconf documentation is useful here.  In configure.ac we use
> AC_PROG_AWK
> (https://www.gnu.org/savannah-checkouts/gnu/autoconf/manual/autoconf-2.69/html_node/Particular-Programs.html).
>  

I think we're good on portable awk now.

> For sed, we do not use AC_PROG_SED, but instead wrote our own macro
> OCTAVE_PROG_SED which is in m4/acinclude.m4.  The top of this macro has
> 
> dnl
> dnl Find sed program.
> dnl
> # Check for a fully-functional sed program, that truncates
> # as few characters as possible and that supports "\(X\|Y\)"
> # style regular expression alternation.  Prefer GNU sed if found.
> 
> Clearly, we are already trying to test for a sed which supports alternation
> and for some reason it is failing?

Thanks, I agree. I read through this macro and it's clear to me now how
it is working and what it is testing for. I now think it may be working
correctly, the failures I saw before may have been due to awk rather
than sed.

Carlo, is SED=gsed still required for the latest builds (no sed-related
changes have been made yet, only awk), and if so, can you tell exactly
which sed syntaxes are failing in which build scripts? The buildbot is
*not* setting SED=gsed in its environment now, and configure is
automatically finding and using /usr/local/bin/sed. Is that ok? Any more
problems?

-- 
mike