Scan a range via a wildcard and returns hostname as well as IP:

nmap -sP 192.168.1.*

Scan a range via a slash notation and returns hostname as well as IP:

nmap -sP 192.168.1.1/24

Scan a range via a slash notation and checks if ports 80 and 8080 are open and returns hostname as well as IP:

sudo nmap -v -O 192.168.1.1/24 -p80,8080

Scans all ports on 192.168.1.1 in verbose mode using the -v flag:

nmap -v 192.168.1.1

Scans all ports on 192.168.1.1 in verbose mode using the -v flag and attempts to detect OS via the -O flag:

sudo nmap -v -O 192.168.1.1

Scanning multiple hosts with grepable output to simply show port status:

nmap -p 27017 -oG - example1.com example2.com example3.com example4.com | grep Ports

---

Port scanning a specific host.

A standard TCP port scan:

sudo nmap -sS -Pn -p- -T4 -vv --reason -oN ~/nmap.TCP.results example.com

A standard UDP port scan:

sudo nmap -sU -Pn -p- -T4 -vv --reason -oN ~/nmap.UDP.results example.com

A scan designed to attempt to discover versions of services on the server:

sudo nmap -sV -Pn -p 22,80 -vv --reason -oN ~/nmap.SERVICE.results example.com