Re: How to replicate the old unix chat?

> TALK(1)                   BSD General Commands Manual
> TALK(1)

> NAME
>      talk — talk to another user

> SYNOPSIS
>      talk person [ttyname]

> DESCRIPTION
>      Talk is a visual communication program which copies lines from your
> ter‐
>      minal 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’ or
> ‘pts/X’.

>      When first called, talk contacts the talk daemon on the other user's
>      machine, which 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 that user. At this point, he then replies by typing

>            talk  your_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; their output will appear in separate
>      windows.  Typing control-L (^L) will cause the screen to be reprinted.
>      The erase, kill line, and word erase characters (normally ^H, ^U, and
> ^W
>      respectively) will behave normally.  To exit, just type the interrupt
>      character (normally ^C); talk then moves the cursor to the bottom of
> the
>      screen and restores the terminal to its previous state.

>      As of netkit-ntalk 0.15 talk supports scrollback; use esc-p and esc-n
> to
>      scroll your window, and ctrl-p and ctrl-n to scroll the other window.
>      These keys are now opposite from the way they were in 0.16; while this
>      will probably be confusing at first, the rationale is that the key
> combi‐
>      nations with escape are harder to type and should therefore be used to
>      scroll one's own screen, since one needs to do that much less often.

>      If you do not want to receive talk requests, you may block them using
> the
>      mesg(1) command.  By default, talk requests are normally not blocked.
>      Certain commands, in particular nroff(1), pine(1), and pr(1), may
> block
>      messages temporarily in order to prevent messy output.

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

> SEE ALSO
>      mail(1), mesg(1), who(1), write(1), talkd(8)

> BUGS
>      The protocol used to communicate with the talk daemon is braindead.

>      Also, the version of talk(1) released with 4.2BSD uses a different and
>      even more braindead protocol that is completely incompatible. Some
> vendor
>      Unixes (particularly those from Sun) have been found to use this old
> pro‐
>      tocol.

>      Old versions of talk may have trouble running on machines with more
> than
>      one IP address, such as machines with dynamic SLIP or PPP connections.
>      This problem is fixed as of netkit-ntalk 0.11, but may affect people
> you
>      are trying to communicate with.

> HISTORY
>      The talk command appeared in 4.2BSD.

> Linux NetKit (0.17)            November 24, 1999           Linux NetKit
> (0.17)