The information you require about getting /usr/bin/talk
working in Yosemite can be found in the ntalkd(8)
man page.
An excerpt from that page reads:
Execute the following command as root to enable talkd: launchctl load -w /System/Library/LaunchDaemons/ntalk.plist
I did this, and was then able to issue a talk nevin
command in one Terminal window, and received the following notice in another Terminal window:
Message from Talk_Daemon@nevin-mac-mini.local at 23:46 on 2015/09/14 ... talk: connection requested by nevin@localhost talk: respond with: talk nevin@localhost
Taking that action in the second terminal window gave me the familiar split-screen talk window. There were no further "Waiting for invitation..." messages.
To turn off ntalkd
, I used:
launchctl unload -w /System/Library/LaunchDaemons/ntalk.plist