Is there a command similar to mkfifo but for domain sockets?
4 Answers
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.
Most recent netcat (nc) and similar programs (socat as far as I know) have domain socket options.
Else, you can have a look at ucspi-unix
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You can use python:
python -c "import socket as s; sock = s.socket(s.AF_UNIX); sock.bind('/tmp/test.sock')"
Also C, see this answer.
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mksock() { SOCK="$1" python -c "import os, socket as s; s.socket(s.AF_UNIX).bind(os.environ['SOCK'])"; }
for easy shell use:mksock /tmp/test.sock
– TinoJul 21, 2019 at 12:39
I simply use netcat
and stay listening in such a case:
nc -lkU aSocket.sock
you should use netcat-openbsd. netcat-traditional does not have -U
switch which is for Unix Domain socket.
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2-k Forces nc to stay listening for another connection after its current connection is completed. It is an error to use this option without the -l option. -U Specifies to use UNIX-domain sockets. Aug 29, 2019 at 15:01
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Why, then, doesn't the
-k
option automatically turn on the-l
option? Jun 9, 2021 at 1:28