To scan a single IP address or host using the nmap command, you can use the following syntax:
nmap target
Replace target with the IP address or hostname that you want to scan.
For example, to scan the IP address 192.168.1.1, you can use the following command:
nmap 192.168.1.1
To scan a hostname, you can use the hostname as the target. For example, to scan the host www.example.com, you can use the following command:
nmap www.example.com
By default, nmap will perform a basic scan that checks for common open ports on the target. You can use various options to customize the scan, such as specifying specific ports to scan, or using different scan techniques.
For example, to scan specific ports, you can use the -p option followed by a comma-separated list of ports. For example:
nmap -p 80,443 www.example.com
This will scan the host www.example.com for open ports 80 and 443 (HTTP and HTTPS).
You can also use the -sT option to perform a TCP connect scan, or the -sS option to perform a SYN scan.
For a complete list of options and more information about using the nmap command, you can use the --help option. For example:
nmap --help
This will display a list of all available options and their descriptions.