Re: [Xen-devel] [PATCH] build: fix sed usage in build process

["Jan Beulich" <JBeulich@xxxxxxxx>]

>>> On 25.03.14 at 16:58, <roger.pau@xxxxxxxxxx> wrote:
> On 25/03/14 15:06, Jan Beulich wrote:
>>>>> On 25.03.14 at 12:20, <roger.pau@xxxxxxxxxx> wrote:
>>> FreeBSD sed is not able to correctly parse the script
>>> '/[0-9]/{s,00*,0,g;p}', so break it into two smaller scripts which
>>> FreeBSD (and Linux) sed is able to parse.
>> 
>> First of all - is this again a standard conformance issue? I can't see
>> what's non-conformant with the old approach (which btw had been
>> in place for quite long a time, so I'm puzzled by this being an issue
>> only now), and for future reference purposes it would be nice to
>> know what exactly should be avoided (i.e. to prevent a similar issue
>> from getting introduced again later).
> 
> Sorry, my regex skills are quite basic. The error is the following:
> 
> sed: 1: "/[0-9]/{s,00*,0,g;p}": extra characters at the end of p command

Perhaps there's just a ; missing after the p?

>> And I take it that you adding -r and the use of + isn't really necessary
>> either - the 00* approach should work equally well without using the
>> non-standard (but apparently more wide spread) -r? (Yes, we're just
>> about to commit other uses of -r, but there the alternative would be
>> more difficult to grok, so has better justification.)
> 
> I just thought the use of 0+ was clearer than 00*, but if you prefer to
> avoid using -r in more places the following expression also works on
> FreeBSD and is more similar to the original one:
> 
> sed -ne 's/00*/0/g' -e '/[0-9]/p'
> 
> If you think this is a suitable solution I can resend the patch.

Yeah, I think we should try to avoid using extensions unless this
provides a real benefit.

Jan


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