Re: sed --posix does not catch incomplete arguments

[Eric Blake]

On 06/11/2010 03:10 PM, Ralf Wildenhues wrote:
> Hello Bruno,
> 
> * Bruno Haible wrote on Fri, Jun 11, 2010 at 09:41:27PM CEST:
>> Quoting <http://www.opengroup.org/onlinepubs/9699919799/utilities/sed.html>:
>>   "-e  script
>>                Add the editing commands specified by the script
>>                option-argument to the end of the script of editing commands.
>>                The script option-argument shall have the same properties as
>>                the script operand, described in the OPERANDS section."
>>
>> Since "sed '1{'" is invalid
>>
>>   $ sed '1{'
>>   sed: -e expression #1, char 0: unmatched `{'
>>   $ sed --posix '1{'
>>   sed: -e expression #1, char 0: unmatched `{'
>>
>> passing the script '1{' to option -e is also invalid.
> 
> Ouch.  That would be a problem, because not splitting brace arguments to
> multiple -e options (or introducing embedded newlines) is not portable
> to some non-GNU seds.  IIRC.  I'll check.  GNU software uses this in
> a few cases, esp. in makefiles of course.

About the only portable alternative that I could think of for a makefile
would be to use multiple echo (or printf) into a temporary file, then
use sed -f file, rather than relying on multiple -e.  The Austin group
take this morning is that allowing -e fragments is a useful addition for
the next revision of the standard, but that there are still
implementations today (like AIX) that don't support it now, so it will
be several years before sed -e 1{ -e } is standardized.

-- 
Eric Blake   address@hidden    +1-801-349-2682
Libvirt virtualization library http://libvirt.org

signature.asc
Description: OpenPGP digital signature