Best run with elevated privileges. Nmap compatibility, run masscan --nmap to find out more.
# To scan an IP or network subnet for port 80:
masscan <ip_address|network_prefix> --ports <80>
# To scan a class B subnet for the top 100 ports at 100,000 packets per second:
masscan <10.0.0.0/16> --top-ports <100> --rate <100000>
# To scan a class B subnet avoiding ranges from a specific exclude file:
masscan <10.0.0.0/16> --top-ports <100> --excludefile <path/to/file>
# To scan the Internet for port 443:
masscan <0.0.0.0/0> --ports <443> --rate <10000000>
# To scan the Internet for a specific port range and export to a file:
masscan <0.0.0.0/0> --ports <0-65535> -output-format <binary|grepable|json|list|xml> --output-filename <path/to/file>