Altering script to print input data with the results of the query (add IP address to NSlookup data)

cilbuper · 10-30-2016, 09:09 PM

I have a script that does most of what I want, get the hostname of an IP address. the script is:

Code:

#!/bin/bash
for ips in `echo 10.10.130.{1..254}`;do
     nslookup $ips;
done | grep name | awk '{print $4}'

If I do an nslookup of 8.8.8.8

Code:

$># nslookup 8.8.8.8
Server:         127.0.1.1
Address:        127.0.1.1#53

Non-authoritative answer:
8.8.8.8.in-addr.arpa    name = google-public-dns-a.google.com.

Authoritative answers can be found from:

The result on the screen would be:

Code:

google-public-dns-a.google.com.

I want it to show the IP address corresponding to the name like:

google-public-dns-a.google.com. 8.8.8.8
or
8.8.8.8 google-public-dns-a.google.com.

I'm not sure which would be better for formatting. I want to be able to put this in a spreadsheet later and have the IP address in one column and the name in another.

What would be the best way of doing this?

Turbocapitalist · 10-30-2016, 10:32 PM

Your "awk" usage could also include the pattern search so you don't need the extra grep.

Code:

nslookup 8.8.8.8 | awk '/name =/ { sub( /\.in.*$/, "", $1 ); sub(/\.$/, "", $4 ); printf( "%s\t%s\n", $1, $4); } '

If you put it inside the loop as well, then you could even use it to extract other information from the query.

perl and other scripting langauges have DNS APIs if things get much more complex than that.

cilbuper · 10-30-2016, 11:18 PM

Quote:

Originally Posted by Turbocapitalist

Your "awk" usage could also include the pattern search so you don't need the extra grep.

Code:

nslookup 8.8.8.8 | awk '/name =/ { sub( /\.in.*$/, "", $1 ); sub(/\.$/, "", $4 ); printf( "%s\t%s\n", $1, $4); } '

If you put it inside the loop as well, then you could even use it to extract other information from the query.

perl and other scripting langauges have DNS APIs if things get much more complex than that.

Thank you for your help and please excuse my ignorance when it comes to scripting. The output of your code is what I am looking for but I am ignorant as to how I can implement it into what I have with the range values.

One thing I'm not sure is possible is formatting so I can separate the IP and NAME in a spreadsheet. DO I need a comma or something else that can designate the separation? I see I can add " > outputfile.txt " at the end of your code and it saves as a file. That is great.

The thing is I need to check a lot of various ranges and most have the same first 2 octets. (192.168.x.x

123.123.45.100-235
134.143.25-33.100-150
I found I could add " > output.txt " to the script to print to a file.

As it stands now I have to change the IP range each time I run the script, which is OK but I have like 100 or so ranges to look at.
I don't mind making a list of all the IP addresses and saving them in a file if that would be easier. I could do that as well - OR - a file with the IP ranges would be nice as well.

Turbocapitalist · 10-30-2016, 11:27 PM

Quote:

Originally Posted by cilbuper

As it stands now I have to change the IP range each time I run the script, which is OK but I have like 100 or so ranges to look at.

You could use a variable in place of the IP number like you have in the original script.

You can combine that with reading a long list of IP numbers from a file, if reading a file is how you want to get your data.

Code:

while read -r ip; do
   echo $ip
done < "$file"

grail · 10-31-2016, 03:00 AM

Spreadsheet input should not be an issue as on the import just tell it that the separator is a space.
A cut down awk could be:

Code:

nslookup 8.8.8.8 | awk '/name/{print gensub(/.in.*/,"",1,$1),$4}'

As for your ips, how about using arrays:

Code:

ips=(123.123.45.{100..235} 134.143.{25..33}.{100..150})

for ip in "${ips[@]}"
do
  nslookup "$ip" | awk '/name/{print gensub(/.in.*/,"",1,$1),$4}'
done

Turbocapitalist · 10-31-2016, 03:06 AM

A sub() or equivalent is also needed for $4 to get rid of the trailing dot.

grail · 10-31-2016, 04:13 AM

Good call ... didn't see that one

Code:

nslookup 8.8.8.8 | awk '/name/{print gensub(/.in[^ ]*|\.$/,"","g",$1" "$4)}'

MadeInGermany · 10-31-2016, 11:41 AM

Even shorter

Code:

for ip in 123.123.45.{100..235} 134.143.{25..33}.{100..150}
do
  host "$ip"
done