First of all, you should get the “nmap” package installed in your system.
yum install nmap
apt-get install nmap
sudo apt-get install nmap
sudo nmap -sS [IP address] or [website address]
sudo nmap -O --osscan-guess [IP address] or [website address]
sudo nmap -vv [IP address] or [website address]
sudo nmap -sV [IP address] or [website address]
nmap -sn 192.168.1.0/24 or nmap -sP 192.168.1.0/24
Zenmap – A GUI for Nmap
All the above is good and you can dive deeper trying out various options and see what you can learn about a target, but for those that want a more user-friendly approach they should install the “zenmap” package that is a GUI tool for Nmap.
Besides the fact that Zenmap offers convenient boxes to insert your target’s IP (or website address) and outputs results in a more eye-pleasing way and with proper highlighting, its main advantage is the fact that it offers pre-set Nmap commands that you can quickly select and run. Moreover, the software offers a test comparison tool, a topology plotter, and the ability to save scans for administrator review and evaluation.
nmap -sP 192.168.2.1/24