Talkd and the talk command
The "talk" command allows you to talk to other users on the same system, which is useful if you're both SSH'd in from somewhere. Using it is very simple; to talk to someone the command is just
talk <username> <tty>
However, getting it working requires some setup.
1. First, install the inetutils package, which contains talk and talkd. These also rely on xinetd, so install that as well. You might also need the screen command; it's in the screen package.
pacman -S inetutils xinetd screen
2. Configure the xinetd service entry in /etc/xinetd.d/talk by setting "disable = no" in /etc/xinetd.d/talk.
3. If you are using tcp_wrappers or something similar, Add an allow entry like this:
4. Now start xinetd:
systemctl start xinetd.service
5. If you're on the local system, you might need to start a screen session to make yourself show up on the "w" and "who" commands -- you need to show up there or talk won't work.
6. Allow write access in your terminal:
Talk should work now.