help with AWk

[Wayne Sierke]

On Sat, 2008-09-27 at 22:06 -0500, Len Conrad wrote:
> The logic desired if
> 
> If IP has no PTR, print "PTR_NUL", else print the PTR.
> 
> 
> dig +short -x 1.2.3.4 | awk '{if ( $0 == "" ) {print "PTR_NUL" } else {print $0 } }'
> 
> ... works if PTR exist, but if no PTR, PTR_NUL doesn't print.
> 
> thanks
> Len

> dig +short -x 10.0.0.1 | awk '{print $0} END {if(NR==0) print "PTR_NUL"}'
PTR_NUL
> dig +short -x 69.147.83.33 | awk '{print $0} END {if(NR==0) print "PTR_NUL"}'
www.freebsd.org.