如何使用UNIX或Linux命令行选项识别远程服务器操作系统和应用程序？
您可以在UNIX，OS X，BSD或Linux操作系统下使用nmap命令来检测远程操作系统和正在运行的应用程序。
输入以下命令

# nmap -O -v localhost
# nmap -O -v server.ip.address

输出示例：

Starting Nmap 5.00 ( http://nmap.org ) at 2010-06-11 04:18 IST
NSE: Loaded 0 scripts for scanning.
Warning: Hostname localhost resolves to 2 IPs. Using 127.0.0.1.
Initiating SYN Stealth Scan at 04:18
Scanning localhost (127.0.0.1) [1000 ports]
Discovered open port 80/tcp on 127.0.0.1
Discovered open port 3306/tcp on 127.0.0.1
Discovered open port 631/tcp on 127.0.0.1
Completed SYN Stealth Scan at 04:18, 0.09s elapsed (1000 total ports)
Initiating OS detection (try #1) against localhost (127.0.0.1)
Retrying OS detection (try #2) against localhost (127.0.0.1)
Retrying OS detection (try #3) against localhost (127.0.0.1)
Retrying OS detection (try #4) against localhost (127.0.0.1)
Retrying OS detection (try #5) against localhost (127.0.0.1)
Host localhost (127.0.0.1) is up (0.000026s latency).
Interesting ports on localhost (127.0.0.1):
Not shown: 997 closed ports
PORT     STATE SERVICE
80/tcp   open  http
631/tcp  open  ipp
3306/tcp open  mysql
No exact OS matches for host (If you know what OS is running on it, see http://nmap.org/submit/ ).
TCP/IP fingerprint:
OS:SCAN(V=5.00%D=6/11%OT=80%CT=1%CU=30822%PV=N%DS=0%G=Y%TM=4C116BC7%P=i686
OS:pc-linux-gnu)SEQ(SP=C9%GCD=1%ISR=CF%TI=Z%CI=Z%II=I%TS=8)OPS(O1=M400CST11
OS:NW6%O2=M400CST11NW6%O3=M400CNNT11NW6%O4=M400CST11NW6%O5=M400CST11NW6%O6=
OS:M400CST11)WIN(W1=8000%W2=8000%W3=8000%W4=8000%W5=8000%W6=8000)ECN(R=Y%DF
OS:=Y%T=40%W=8018%O=M400CNNSNW6%CC=Y%Q=)T1(R=Y%DF=Y%T=40%S=O%A=S+%F=AS%RD=0
OS:%Q=)T2(R=N)T3(R=Y%DF=Y%T=40%W=8000%S=O%A=S+%F=AS%O=M400CST11NW6%RD=0%Q=)
OS:T4(R=Y%DF=Y%T=40%W=0%S=A%A=Z%F=R%O=%RD=0%Q=)T5(R=Y%DF=Y%T=40%W=0%S=Z%A=S
OS:+%F=AR%O=%RD=0%Q=)T6(R=Y%DF=Y%T=40%W=0%S=A%A=Z%F=R%O=%RD=0%Q=)T7(R=Y%DF=
OS:Y%T=40%W=0%S=Z%A=S+%F=AR%O=%RD=0%Q=)U1(R=Y%DF=N%T=40%IPL=164%UN=0%RIPL=G
OS:%RID=G%RIPCK=G%RUCK=G%RUD=G)IE(R=Y%DFI=N%T=40%CD=S)

Uptime guess: 0.527 days (since Thu Jun 10 15:39:23 2010)
Network Distance: 0 hops
TCP Sequence Prediction: Difficulty=201 (Good luck!)
IP ID Sequence Generation: All zeros

Read data files from: /usr/share/nmap
OS detection performed. Please report any incorrect results at http://nmap.org/submit/ .
Nmap done: 1 IP address (1 host up) scanned in 12.11 seconds
           Raw packets sent: 1095 (51.990KB) | Rcvd: 2208 (98.632KB)