Using unix sockets to connect from your irc client
Some IRC clients such as irssi allow you to connect to unix sockets, which have filesystem paths instead of hostnames as addresses.
BitlBee doesn't exactly support this, but there are workarounds.
With systemd socket activation and inetd mode
Just change the ListenStream entry of the bitlbee.socket unit to be a filesystem path instead of a port number.
Example contents of bitlbee.socket
[Socket] ListenStream=/run/bitlbee.sock Accept=yes
Example contents of bitlbee@.service (no need to change anything)
[Unit] Description=BitlBee Per-Connection Server After=syslog.target [Service] ExecStart=/usr/sbin/bitlbee -I StandardInput=socket User=bitlbee
If you don't have these, just place them with /etc/systemd/system/. Then just enable and start bitlbee.socket. (not the service)
systemctl enable bitlbee.socket systemctl start bitlbee.socket
And connect from your irc client with /connect /run/bitlbee.sock
Other methods
As far as I know inetd/xinetd don't support AF_UNIX sockets. Edit this if i'm wrong.