Mastering Go - Second Edition

The nc(1) command-line utility

The nc(1) utility, which is also called netcat(1), comes in very handy when you want to test TCP/IP servers and clients. This section will present some of its more common uses.

You can use nc(1) as a client for a TCP service that runs on a machine with the 10.10.1.123 IP address and listens to port number 1234, as follows:

$ nc 10.10.1.123 1234
  

By default, nc(1) uses the TCP protocol. However, if you execute nc(1) with the -u flag, then nc(1) will use the UDP protocol.

The -l option tells netcat(1) to act as a server, which means that netcat(1) will start listening for connections at the given port number.

Finally, the -v and -vv options tell netcat(1) to generate verbose output, which can come in handy when ...