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Re: dig: single line



On Thu, 2009-03-12 at 00:39 +0000, Mike -- EMAIL IGNORED wrote:
> On Thu, 12 Mar 2009 00:35:03 +0000, Mike -- EMAIL IGNORED wrote:
> 
> > On Wed, 11 Mar 2009 19:46:53 -0430, Patrick O'Callaghan wrote:
> > 
> >> On Thu, 2009-03-12 at 00:13 +0000, Mike -- EMAIL IGNORED wrote:
> >>> On Wed, 11 Mar 2009 19:31:34 -0430, Patrick O'Callaghan wrote:
> >>> 
> >>> > On Wed, 2009-03-11 at 23:32 +0000, Mike -- EMAIL IGNORED wrote:
> >>> >> The head suggestion won't work, because in the above example, it is
> >>> >> the second line I want.
> >>> > 
> >>> > A trivial excercise for old Shell hands, e.g.
> >>> > 
> >>> >         program | head -n 2 | tail -n 1
> >>> > 
> >>> > or
> >>> > 
> >>> >         program | sed -n 2p
> >>> > 
> >>> > poc
> >>> 
> >>> Yes, but the dig command sometimes returns the result on the first
> >>> line, and sometimes on the second, so it is necessary to test what you
> >>> get.
> >> 
> >> You haven't so far said which of the lines you are interested in.
> >> Perhaps you can use grep on a pattern.
> >> 
> >> poc
> > 
> > How about:
> > 
> >    grep "[0-9]+\.[0-9]+\.[0-9]+\.[0-9]"
> > 
> > ?
> > Can it be done more concisely?  Still, one of the numbers might exceed
> > 255 ... unlikely.
> > 
> > Mike.
> 
> I forgot the final + .

You also forgot the initial ^ and final $, without which the match could
trigger on something other than a pure IP number (unlikely in practice
but not impossible e.g. abc.1.2.3.4.example.com).

poc


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