How to write a Ruby script that extracts IPs from a NMAP scan

Asked May 08 '20 at 13:35

Active May 08 '20 at 13:44

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I'm trying to write a script in Ruby that extracts some IP and different informations from a NMAP scan output. I'm using regular expressions and I already know how to properly extract IPs but there's something I'm not fully understanding with the grouping concept.

Let's say I have the current string in the file and I want to extract the IP value:

"Nmap scan report for 10.50.96.1"

Here I'm playing around with pry and building my script to recognize IP:

>> string = "Nmap scan report for 10.50.96.1"
=> "Nmap scan report for 10.50.96.1"
>> test = /(\d{1,3}\.){3}/.match(string)
=> #<MatchData "10.50.96." 1:"96.">

I do not understand why the global variable $1 is set as 96..

Shouldn't I have 3 groups, with the 3 values 10., 50. and 96.?

edited May 08 '20 at 13:44

asked May 08 '20 at 13:35

Mr.Laf

Probably, you need `test = /(\d{1,3})\.(\d{1,3})\.(\d{1,3})\.(\d{1,3})/.match(string)`. Repeated capturing groups only "save" the last value captured. – Wiktor Stribiżew May 08 '20 at 13:37
@WiktorStribiżew ok right, every set of parenthesis is a single group. But why I only have 96. set as a group? – Mr.Laf May 08 '20 at 13:39
See https://stackoverflow.com/questions/37003623/how-to-capture-multiple-repeated-groups – Wiktor Stribiżew May 08 '20 at 13:47
@WiktorStribiżew Ok, thought about it but it seemed a strange behavior in the first place. Thanks! – Mr.Laf May 08 '20 at 13:47

How to write a Ruby script that extracts IPs from a NMAP scan

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