talk — talk to another user

       The  version  of talk(1) released with 4.3BSD uses a protocol that is incompatible with the protocol used
       in the version released with 4.2BSD.

Talk is a visual communication program which copies lines from your terminal to that of another user.

       Options available:

       person   If you wish to talk to someone on your own machine, then person is just the person's login name.
                If you wish to talk to a user on another host, then person is of the form ‘user@host’.

       ttyname  If  you wish to talk to a user who is logged in more than once, the ttyname argument may be used
                to indicate the appropriate terminal name, where ttyname is of the form ‘ttyXX’.

       When first called, talk sends the message
             Message from TalkDaemon@his_machine...
             talk: connection requested by your_name@your_machine.
             talk: respond with: talk your_name@your_machine

       to the user you wish to talk to. At this point, the recipient of the message should reply by typing

             talkyour_name@your_machine

       It doesn't matter from which machine the recipient replies, as long as his login-name is the same.   Once
       communication  is  established,  the  two parties may type simultaneously, with their output appearing in
       separate windows.  Typing control-L ‘^L’ will cause the screen to be reprinted, while your  erase,  kill,
       and  word  kill  characters will behave normally.  To exit, just type your interrupt character; talk then
       moves the cursor to the bottom of the screen and restores the terminal to its previous state.

       Permission to talk may be denied or granted by use of the mesg(1) command.   At  the  outset  talking  is
       allowed.  Certain commands, in particular nroff(1) and pr(1), disallow messages in order to prevent messy
       output.

/etc/hosts
                  to find the recipient's machine
       /run/utmp  to find the recipient's tty

       The talk command appeared in 4.2BSD.

GNU Network Utilities                           February 9, 2019                                         talk(1)

       talk — talk to another user

mail(1), mesg(1), who(1), write(1)

talkperson [ttyname]