Sockets are a special file type, similar to TCP/IP sockets, providing inter-process networking protected by the file system's access control.

For example, when you open a listening socket in one terminal with netcat:

nc -lU socket.sock

then send data from another terminal by:

echo mytext | nc -U socket.sock

mytext appears on the first terminal.

By default nc stops listening after an End-of-File character.