Official VW documentation has an example of how to run Vowpal Wabbit in daemon mode. https://github.com/VowpalWabbit/vowpal_wabbit/wiki/Daemon-example But it seems that VW always binds a particular port to the daemon (by default it is port 26542).
It is possible to use file socket instead of a TCP socket for Vowpal Wabbit daemon mode?
Right now vowpalwabbit explicitly uses TCP sockets in deamon mode so the only thing you can define is the port you wish to use via --port.
PS: I'm a maintainer for this project and we would be more than happy to accept a patch with this if you need it, as we currently don't have plans to support this feature. Here is the related TCP code: https://github.com/VowpalWabbit/vowpal_wabbit/blob/master/vowpalwabbit/parser.cc#L208