使用netcat(瑞士军刀)进行文件传输

nc(netcat)被誉为网络工具中的“瑞士军刀”，体积虽小但功能强大，nc最简单的功能是端口扫描，这里我主要笔记一下它作为文件传输的妙用。

首先看一下帮助信息。

$ nc -h
openbsd netcat (debian patchlevel 1.105-7ubuntu1)
this is nc from the netcat-openbsd package. an alternative nc is available
in the netcat-traditional package.
usage: nc [-46bcddhjklnrstuuvzz] [-i length] [-i interval] [-o length]
   [-p proxy_username] [-p source_port] [-q seconds] [-s source]
   [-t toskeyword] [-v rtable] [-w timeout] [-x proxy_protocol]
   [-x proxy_address[:port]] [destination] [port]
  command summary:
    -4    use ipv4
    -6    use ipv6
    -b    allow broadcast
    -c    send crlf as line-ending
    -d    enable the debug socket option
    -d    detach from stdin
    -h    this help text
    -i length  tcp receive buffer length
    -i secs    delay interval for lines sent, ports scanned
    -j    use jumbo frame
    -k    keep inbound sockets open for multiple connects
    -l    listen mode, for inbound connects
    -n    suppress name/port resolutions
    -o length  tcp send buffer length
    -p proxyuser  username for proxy authentication
    -p port    specify local port for remote connects
      -q secs    quit after eof on stdin and delay of secs
    -r    randomize remote ports
    -s    enable the tcp md5 signature option
    -s addr    local source address
    -t toskeyword  set ip type of service
    -t    answer telnet negotiation
    -u    use unix domain socket
    -u    udp mode
    -v rtable  specify alternate routing table
    -v    verbose
    -w secs    timeout for connects and final net reads
    -x proto  proxy protocol: "4", "5" (socks) or "connect"
    -x addr[:port]  specify proxy address and port
    -z    dccp mode
    -z    zero-i/o mode [used for scanning]
  port numbers can be individual or ranges: lo-hi [inclusive]

端口扫描：

$ nc -z -v -n 127.0.0.1 20-100
...
connection to 127.0.0.1 80 port [tcp/*] succeeded!
...

简单文件传输：

客户端：

$ nc -l 192.168.1.11 1234 > passwd.txt &

服务端：

$ nc 192.168.1.11 1234 < /etc/passwd

也可以是

cat /etc/passwd | nc 192.168.1.11 1234

服务端ip是192.169.1.11，端口是1234

如此，当两台linux机器需要简单传输文件时，再好不过了～