`nc` is the "network `cat`" program, connecting Unix pipe I/O to TCP and UDP sockets.
nc is like
cat for TCP/IP networking. It is often used with Unix processes that do not have built-in networking but which can do regular Unix pipe style I/O, allowing them to talk to the network instead.
There is no standard version of
nc, so your system might have a competing variant of the program. Common names are