Digging to the final IP

[Niall O'Reilly]

At Thu, 23 Oct 2014 15:17:49 +0100,
Sam Wilson wrote:
> 
> In article <mailman.1128.1414072988.26362.bind-users at lists.isc.org>,
>  Bob Harold <rharolde at umich.edu> wrote:
> 
> > Anytime you see 'grep' and 'cut' used together, they can usually be
> > shortened to just 'awk', which requires starting one less process.  And if
> > this case it splits fields the way a users sees them, so the same code
> > works in both cases:
> > 
> > $ dig +noall +answer home.kreme.com in a | awk '/[\t ]A[\t ]/ {print $NF}'
> > 23.24.150.141
> > $ dig +noall +answer  dave.knig.ht in a | awk '/[\t ]A[\t ]/ {print $NF}'
> > 216.235.14.46
> 
> $ dig +noall +answer cancer.ucs.ed.ac.uk | perl -ne ' /\sA\s/ && do { 
> @_=split; print "$_[$#_]\n" }' 
> 129.215.166.13
> 129.215.200.7

  Which makes it easy, in either case, to return a status value, as
  Frank Bulk seemed to want.

  Something like

  '... {print $NF; count++} END {exit ! count}'

  or

  | perl -ane ' /\sA\s/ && do { print "$F[$#F]\n"; $count++ } END
    {exit ! $count }'

  might work.

  Niall