NMAP

Option	Full Command	Description
-v	nmap -v [target]	Verbose output
-O	nmap -O [target]	OS detection
-sS	nmap -sS [target]	Fast scan
-sT	nmap -sT [target]	Half-scan, doesn't complete tcp handshake
-sU	nmap -sU [target]	Full scan, completeds tcp handshake
-sA	nmap -sA [target]	Firewall identification
-sV	nmap -sV [target]	Finds service on each responding port