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.\"     @(#)talk.1	8.1 (Berkeley) 6/6/93
.\" $FreeBSD$
.\"
.Dd June 6, 1993
.Dt TALK 1
.Os
.Sh NAME
.Nm talk
.Nd talk to another user
.Sh SYNOPSIS
.Nm
.Ar person
.Op Ar ttyname
.Sh DESCRIPTION
The
.Nm
utility is a visual communication program which copies lines from your
terminal to that of another user.
.Pp
Options available:
.Bl -tag -width ttyname
.It Ar person
If you wish to talk to someone on your own machine, then
.Ar person
is just the person's login name.
If you wish to talk to a user on
another host, then
.Ar person
is of the form
.Ql user@host
or
.Ql host!user
or
.Ql host:user .
.It Ar ttyname
If you wish to talk to a user who is logged in more than once, the
.Ar ttyname
argument may be used to indicate the appropriate terminal
name, where
.Ar ttyname
is of the form
.Ql ttyXX .
.El
.Pp
When first called,
.Nm
sends the message
.Bd -literal -offset indent -compact
Message from TalkDaemon@his_machine...
talk: connection requested by your_name@your_machine.
talk: respond with: talk your_name@your_machine
.Ed
.Pp
to the user you wish to talk to.
At this point, the recipient
of the message should reply by typing
.Pp
.Dl talk \ your_name@your_machine
.Pp
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
.Ql ^L
will cause the screen to
be reprinted.
Typing control-D
.Ql ^D
will clear both parts of your screen to be cleared, while
the control-D character will be sent to the remote side
(and just displayed by this
.Nm
client).
Your erase, kill, and word kill characters will
behave normally.
To exit, just type your interrupt character;
.Nm
then moves the cursor to the bottom of the screen and restores the
terminal to its previous state.
.Pp
Permission to talk may be denied or granted by use of the
.Xr mesg 1
command.
At the outset talking is allowed.
.Sh FILES
.Bl -tag -width /var/run/utmp -compact
.It Pa /etc/hosts
to find the recipient's machine
.It Pa /var/run/utmp
to find the recipient's tty
.El
.Sh SEE ALSO
.Xr mail 1 ,
.Xr mesg 1 ,
.Xr wall 1 ,
.Xr who 1 ,
.Xr write 1 ,
.Xr talkd 8
.Sh BUGS
The version of
.Nm
released with
.Bx 4.3
uses a protocol that
is incompatible with the protocol used in the version released with
.Bx 4.2 .
.Sh HISTORY
The
.Nm
command appeared in
.Bx 4.2 .
.Pp
In
.Fx 5.2 ,
the default behaviour of
.Nm
was changed to treat local-to-local talk requests as originating
and terminating at
.Em localhost .
Before this change, it was required that the hostname (as per
.Xr gethostname 3 )
resolved to a valid IPv4 address (via
.Xr gethostbyname 3 ) ,
making
.Nm
unsuitable for use in configurations where
.Xr talkd 8
was bound to the loopback interface (normally for security reasons).