How to portscan with nnmap

nmap -P0 -p0-65535 127.0.0.1

-P0 == dont try to ping
-p == port range (note that its 0-65535)

obligatory man page posting:

Nmap 3.81 Usage: nmap [Scan Type(s)] [Options]
Some Common Scan Types ('*' options require root privileges)
* -sS TCP SYN stealth port scan (default if privileged (root))
-sT TCP connect() port scan (default for unprivileged users)
* -sU UDP port scan
-sP ping scan (Find any reachable machines)
* -sF,-sX,-sN Stealth FIN, Xmas, or Null scan (experts only)
-sV Version scan probes open ports determining service & app names/versions
-sR RPC scan (use with other scan types)
Some Common Options (none are required, most can be combined):
* -O Use TCP/IP fingerprinting to guess remote operating system
-p ports to scan. Example range: 1-1024,1080,6666,31337
-F Only scans ports listed in nmap-services
-v Verbose. Its use is recommended. Use twice for greater effect.
-P0 Don't ping hosts (needed to scan www.microsoft.com and others)
* -Ddecoy_host1,decoy2[,...] Hide scan using many decoys
-6 scans via IPv6 rather than IPv4
-T General timing policy
-n/-R Never do DNS resolution/Always resolve [default: sometimes resolve]
-oN/-oX/-oG Output normal/XML/grepable scan logs to
-iL Get targets from file; Use '-' for stdin
* -S /-e Specify source address or network interface
--interactive Go into interactive mode (then press h for help)
Example: nmap -v -sS -O www.my.com 192.168.0.0/16 '192.88-90.*.*'