I know how to use nmap to find the list of hosts that are currently online. What I would like to do is get a list of just their IP addresses, now it displays extra information such as

Nmap scan report for 192.168.x.x' and 'Host is up (0.12s latency).

What I would like is to be able to run an nmap command, get a text document of the IP addresses that are currently online.

Is this at all possible?

migrated from serverfault.com Jan 28 '15 at 22:04

This question came from our site for system and network administrators.

This is a common one:

nmap -n -sn 192.0.2.0/24 -oG - | awk '/Up$/{print $2}'

Quick rundown of options and commands:

  • -n turns off reverse name resolution, since you just want IP addresses. On a local LAN this is probably the slowest step, too, so you get a good speed boost.
  • -sn means "Don't do a port scan." It's the same as the older, deprecated -sP with the mnemonic "ping scan."
  • -oG - sends "grepable" output to stdout, which gets piped to awk.
  • /Up$/ selects only lines which end with "Up", representing hosts that are online.
  • {print $2} prints the second whitespace-separated field, which is the IP address.
  • This worked perfectly, thanks! – RoboCop87 Sep 9 at 15:35

You could pipe it to awk:

nmap -sP 192.168.1.0/24 | awk '/is up/ {print up}; {gsub (/\(|\)/,""); up = $NF}'
192.168.1.1
192.168.1.10
192.168.1.20
192.168.1.30

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