pingns

#!/bin/sh

if [ -n "$1" ]; then
    num="$1"
    shift
else
    num=1
fi

ns=$( perl -0777ne 'my @ns = /^ *nameserver +([0-9.]+)/mg; 
                    print $ns['$num' - 1] || ""' \
                    /etc/resolv.conf )

if [ -z "$ns" ]; then
  echo "Could not find nameserver $num in /etc/resolv.conf" >&2
  exit 1
fi

ping "$@" "$ns"