Netcat实用技巧-优快云博客

原贴:http://cb.vu/unixtoolbox.xhtml#ssh

Netcat

Netcat http://netcat.sourceforge.net (nc) is better known as the "network Swiss Army Knife", it can manipulate, create or read/write TCP/IP connections. Here some useful examples, there are many more on the net, for example g-loaded.eu[...] http://www.g-loaded.eu/2006/11/06/netcat-a-couple-of-useful-examples and here http://www.terminally-incoherent.com/blog/2007/08/07/few-useful-netcat-tricks.
You might need to use the command netcat instead of nc. Also see the similar command socat.

File transfer

Copy a large folder over a raw tcp connection. The transfer is very quick (no protocol overhead) and you don't need to mess up with NFS or SMB or FTP or so, simply make the file available on the server, and get it from the client. Here 192.168.1.1 is the server IP address.

server# tar -cf - -C VIDEO_TS . | nc -l -p 4444         # Serve tar folder on port 4444
client# nc 192.168.1.1 4444 | tar xpf - -C VIDEO_TS     # Pull the file on port 4444
server# cat largefile | nc -l 5678                      # Server a single file
client# nc 192.168.1.1 5678 > largefile                 # Pull the single file
server# dd if=/dev/da0 | nc -l 4444                     # Server partition image
client# nc 192.168.1.1 4444 | dd of=/dev/da0            # Pull partition to clone
client# nc 192.168.1.1 4444 | dd of=da0.img             # Pull partition to file

Other hacks

Specially here, you must know what you are doing.

Remote shell

Option -e only on the Windows version? Or use nc 1.10.

# nc -lp 4444 -e /bin/bash                        # Provide a remote shell (server backdoor)
# nc -lp 4444 -e cmd.exe                          # remote shell for Windows

Emergency web server

Serve a single file on port 80 in a loop.

# while true; do nc -l -p 80 < unixtoolbox.xhtml; done

Chat

Alice and Bob can chat over a simple TCP socket. The text is transferred with the enter key.

alice# nc -lp 4444
bob  # nc 192.168.1.1 4444