nmap helpful hints

  nmap -v -n -r -sS -PO [more stuff] {target}

    -v = verbose
    -n = never reverse DNS lookup (-R = always lookup)
    -r = don't randomize port scan
    -sS = SYN scan (default, fast, requires root)
    -P0 = skip host discovery pass (P-zero)

    target can be a hostname, IP address, network w/ CIDR, etc
    -iL  for a list of targets in a file

    -oG  = greppable output (-oG - for STDOUT)
    -O = attempt OS fingerprinting
    -p80 = port 80 only
    -p1-1024 = ports 1-1024 only
    -sV = determine service/version info
    -vv = more verbosity
    -d[level] = debugging, level (1-9)