EXAMPLES:
1. nmap -v -A sina.com

 -v: Increase verbosity level (use -vv or more for greater effect)

-A: Enable OS detection, version detection, script scanning, and traceroute

2.nmap -v -sn 192.168.0.0/16 10.0.0.0/8

-sn: Ping Scan - disable port scan

3.nmap -v 192.168.100.0/24 -Pn -p 80-100

 -Pn: Treat all hosts as online -- skip host discovery

 -p <port ranges>: Only scan specified ports

Usage: nmap [Scan Type(s)] [Options] {target specification}TARGET SPECIFICATION:  Can pass hostnames, IP addresses, networks, etc.  Ex: scanme.nmap.org, microsoft.com/24, 192.168.0.1; 10.0.0-255.1-254  -iL 
     
      : Input from list of hosts/networks  -iR 
      
       : Choose random targets  --exclude 
       
        : Exclude hosts/networks  --excludefile 
        
         : Exclude list from fileHOST DISCOVERY:  -sL: List Scan - simply list targets to scan  -sn: Ping Scan - disable port scan  -Pn: Treat all hosts as online -- skip host discovery  -PS/PA/PU/PY[portlist]: TCP SYN/ACK, UDP or SCTP discovery to given ports  -PE/PP/PM: ICMP echo, timestamp, and netmask request discovery probes  -PO[protocol list]: IP Protocol Ping  -n/-R: Never do DNS resolution/Always resolve [default: sometimes]  --dns-servers 
         
          : Specify custom DNS servers  --system-dns: Use OS's DNS resolver  --traceroute: Trace hop path to each hostSCAN TECHNIQUES:  -sS/sT/sA/sW/sM: TCP SYN/Connect()/ACK/Window/Maimon scans  -sU: UDP Scan  -sN/sF/sX: TCP Null, FIN, and Xmas scans  --scanflags 
          
           : Customize TCP scan flags -sI 
           
            : Idle scan -sY/sZ: SCTP INIT/COOKIE-ECHO scans -sO: IP protocol scan -b 
            
             : FTP bounce scanPORT SPECIFICATION AND SCAN ORDER: -p 
             
              : Only scan specified ports Ex: -p22; -p1-65535; -p U:53,111,137,T:21-25,80,139,8080,S:9 -F: Fast mode - Scan fewer ports than the default scan -r: Scan ports consecutively - don't randomize --top-ports 
              
               : Scan 
               
                 most common ports --port-ratio 
                
                 : Scan ports more common than 
                 
                  SERVICE/VERSION DETECTION: -sV: Probe open ports to determine service/version info --version-intensity 
                  
                   : Set from 0 (light) to 9 (try all probes) --version-light: Limit to most likely probes (intensity 2) --version-all: Try every single probe (intensity 9) --version-trace: Show detailed version scan activity (for debugging)SCRIPT SCAN: -sC: equivalent to --script=default --script=
                   
                    : 
                    
                      is a comma separated list of directories, script-files or script-categories --script-args=
                     
                      : provide arguments to scripts --script-args-file=filename: provide NSE script args in a file --script-trace: Show all data sent and received --script-updatedb: Update the script database. --script-help=
                      
                       : Show help about scripts. 
                       
                         is a comma separted list of script-files or script-categories.OS DETECTION: -O: Enable OS detection --osscan-limit: Limit OS detection to promising targets --osscan-guess: Guess OS more aggressivelyTIMING AND PERFORMANCE: Options which take 
                         are in seconds, or append 'ms' (milliseconds), 's' (seconds), 'm' (minutes), or 'h' (hours) to the value (e.g. 30m). -T<0-5>: Set timing template (higher is faster) --min-hostgroup/max-hostgroup 
                         
                          : Parallel host scan group sizes --min-parallelism/max-parallelism 
                          
                           : Probe parallelization --min-rtt-timeout/max-rtt-timeout/initial-rtt-timeout 
                           : Specifies probe round trip time. --max-retries 
                            
                             : Caps number of port scan probe retransmissions. --host-timeout 
                             : Give up on target after this long --scan-delay/--max-scan-delay : Adjust delay between probes --min-rate 
                               
                                : Send packets no slower than 
                                
                                  per second --max-rate 
                                 
                                  : Send packets no faster than 
                                  
                                    per secondFIREWALL/IDS EVASION AND SPOOFING: -f; --mtu 
                                   
                                    : fragment packets (optionally w/given MTU) -D 
                                    
                                     : Cloak a scan with decoys -S 
                                     
                                      : Spoof source address -e 
                                      
                                       : Use specified interface -g/--source-port 
                                       
                                        : Use given port number --data-length 
                                        
                                         : Append random data to sent packets --ip-options 
                                         
                                          : Send packets with specified ip options --ttl 
                                          
                                           : Set IP time-to-live field --spoof-mac 
                                           
                                            : Spoof your MAC address --badsum: Send packets with a bogus TCP/UDP/SCTP checksumOUTPUT: -oN/-oX/-oS/-oG 
                                            
                                             : Output scan in normal, XML, s|
                                             
                                              : Output in the three major formats at once -v: Increase verbosity level (use -vv or more for greater effect) -d: Increase debugging level (use -dd or more for greater effect) --reason: Display the reason a port is in a particular state --open: Only show open (or possibly open) ports --packet-trace: Show all packets sent and received --iflist: Print host interfaces and routes (for debugging) --log-errors: Log errors/warnings to the normal-format output file --append-output: Append to rather than clobber specified output files --resume 
                                              
                                               : Resume an aborted scan --stylesheet 
                                               
                                                : XSL stylesheet to transform XML output to HTML --webxml: Reference stylesheet from Nmap.Org for more portable XML --no-stylesheet: Prevent associating of XSL stylesheet w/XML outputMISC: -6: Enable IPv6 scanning -A: Enable OS detection, version detection, script scanning, and traceroute --datadir 
                                                
                                                 : Specify custom Nmap data file location --send-eth/--send-ip: Send using raw ethernet frames or IP packets --privileged: Assume that the user is fully privileged --unprivileged: Assume the user lacks raw socket privileges -V: Print version number -h: Print this help summary page.