Joel E. Denny wrote:
> On Wed, 5 Aug 2009, Eric Blake wrote:
>
>> > +if ( diff --version < /dev/null 2>&1 | grep GNU ) 2>&1 > /dev/null;
>> > then
>> > + compare() { diff -u "$@"; }
>>
>> 'diff -u' is required by POSIX 2008. Rather than filtering on
>> whether 'diff --version' includes GNU, it would be better to
>> filter on whether 'diff -u' is accepted on the command line,
>> to allow other POSIX-compliant implementations their chance.
>> Something like 'diff -u /dev/null /dev/null' giving no output
>> and having a 0 status should be a sufficient filter.
>
> Thanks. Here's a revised version.
>
>>From 9df97231a6824ab608751e61b05c36279719a21a Mon Sep 17 00:00:00 2001
> From: Joel E. Denny <jde...@clemson.edu>
> Date: Wed, 5 Aug 2009 10:03:10 -0400
> Subject: [PATCH] update-copyright-tests: improve portability
>
> * tests/test-update-copyright.sh: Use cmp if diff cannot handle
> -u or /dev/null. Suggested by Jim Meyering and Eric Blake.
Thanks. Applied.
