What’s going on with a known host?

Normal useful nmap command:

sudo nmap -A example.xed.ch

This needs root. The -A is OS with Version detection. Using -O instead works, but it isn’t as clever and can’t find the OS sometimes.

Looking for unknown hosts on a network range

This will take a long time but produce results about a /24 network:

sudo nmap -A 192.168.1.*
sudo nmap -A

This one is from my updater script. Works pretty fast.

/usr/bin/nmap -sP -oG - | /bin/grep "Status: Up" | /bin/sed "s/^.*(\\(.*\\)).*$/\\1/"