Unix – How to Create a Named Socket from the Command Line
domainsocketunix
Is there a command similar to mkfifo but for domain sockets?
Best Answer
There is no exact equivalent of mkfifo for socket, i.e. there is no command that just creates a "hanging" socket. This is for historical reason: server's function bind(), the one that creates a socket name/inode in the filesystem, fails if the name is already used. In other words, server cannot operate on a pre-existing socket.
So if you'd created socket earlier, it would need to be removed by the server anyway first. No benefit. As you see with Gregory's answer, you can create a socket IF you keep a server for it, such as netcat. Once a server is gone, the old socket is gone. A new server has a new socket, and all clients need to re-connect, despite the socket's name being identical.
A UNIX socket, AKA Unix Domain Socket, is an inter-process communication mechanism that allows bidirectional data exchange between processes running on the same machine.
IP sockets (especially TCP/IP sockets) are a mechanism allowing communication between processes over the network. In some cases, you can use TCP/IP sockets to talk with processes running on the same computer (by using the loopback interface).
UNIX domain sockets know that they’re executing on the same system, so they can avoid some checks and operations (like routing); which makes them faster and lighter than IP sockets. So if you plan to communicate with processes on the same host, this is a better option than IP sockets.
Edit: As per Nils Toedtmann's comment: UNIX domain sockets are subject to file system permissions, while TCP sockets can be controlled only on the packet filter level.
Best Answer
There is no exact equivalent of mkfifo for socket, i.e. there is no command that just creates a "hanging" socket. This is for historical reason: server's function bind(), the one that creates a socket name/inode in the filesystem, fails if the name is already used. In other words, server cannot operate on a pre-existing socket.
So if you'd created socket earlier, it would need to be removed by the server anyway first. No benefit. As you see with Gregory's answer, you can create a socket IF you keep a server for it, such as netcat. Once a server is gone, the old socket is gone. A new server has a new socket, and all clients need to re-connect, despite the socket's name being identical.