Re: GUN Sed Bug

[Eric Blake]

On 10/26/2012 03:06 PM, Eric Blake wrote:
> On 10/26/2012 06:42 AM, 王森 wrote:
> 
>> address@hidden learn_sed]# /bin/sed "s/\'/ End/" tmp.txt
>> hello world End
>> I'am in china End
>> address@hidden learn_sed]#
>> ### My Question
>> I want to know the reason.  \' be equal to Line End ?
> 
> Thanks for the report.  However, this is not a bug, but a GNU extension,
> as documented here:
> https://www.gnu.org/software/sed/manual/html_node/Escapes.html#Escapes
> 
> In your particular case, end of line and end of input happen to match.
> But if your sed script had also used commands like 'N', then you could
> see a difference where multi-line mode makes \' match fewer places than $.

By the way, POSIX says \' in sed is not portable, because
implementations differ on whether it matches a literal ' or is treated
like the GNU extension.  If you were trying to match the literal ', then
lose the backslash in your sed script.

-- 
Eric Blake   address@hidden    +1-919-301-3266
Libvirt virtualization library http://libvirt.org

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