# Check if an IP address is up, and guess the remote host's operating system:
$ nmap -O ip_or_hostname
# Try to determine whether the specified hosts are up (ping scan) and what their names are:
$ nmap -sn ip_or_hostname optional_another_address
# Also enable scripts, service detection, OS fingerprinting and traceroute:
$ nmap -A address_or_addresses
# Scan a specific list of ports (use '-p-' for all ports from 1 to 65535):
$ nmap -p port1,port2,...,portN address_or_addresses
# Perform service and version detection of the top 1000 ports using default NSE scripts; writing results ('-oN') to output file:
$ nmap -sC -sV -oN top-1000-ports.txt address_or_addresses
# Scan target(s) carefully using 'default and safe' NSE scripts:
$ nmap --script "default and safe" address_or_addresses
# Scan web server running on standard ports 80 and 443 using all available 'http-*' NSE scripts:
$ nmap --script "http-*" address_or_addresses -p 80,443
# Perform a stealthy very slow scan ('-T0') trying to avoid detection by IDS/IPS and use decoy ('-D') source IP addresses:
$ nmap -T0 -D decoy1_ipaddress,decoy2_ipaddress,...,decoyN_ipaddress address_or_addresses