.\"	@(#)write.1	2.41
.\"
.TH WRITE 1 "Jan 20, 2000"
.AT 3
.SH NAME
write \- write to another user
.SH SYNOPSIS
.B write
[-ctynsprfSv] [ user [ tty ] ]
.br
.B ojot
[-ltynsprfSv] [ user [ tty ] ]
.br
.B tel
[-clynsprfSv] user [ tty ] [message...]
.SH DESCRIPTION
Note: This is "Orville write", an enhanced version of the standard Unix
.I write
program.

.I Write
copies lines from your terminal to that of
another user.  When first called, it sends the message:
.PP
     Message from your-logname your-tty ...
.PP
The recipient of the message should write back at this point.
Communication continues until an end of file is read from the terminal
or an interrupt is sent.
At that point,
.I write
writes "EOF (your-logname)" on the other terminal and exits.
.PP
The following protocol is strongly suggested for using
.IR write :
when you first write to another user,
wait for him or her to write back before starting to type your message.
Each party should end each message with a distinctive signal
(\fBo\fR for
``over'' is conventional), indicating that the other may reply;
.B oo
for ``over and out'' is suggested when conversation is to be terminated.
Avoid typing when it is the other person's turn, as your text will get
all garbled with theirs.
Anyway, it's rude.
.PP
The
.I ojot
command is a variation of
.I write
which normally
sends each character to the other user as you type it instead of
waiting for you to finish a line before sending anything as write does.
.PP
The
.I tel
command sends one line ``telegrams'' and then immediately disconnects.
The message may be given on the command lines (in which case it is
usually best to quote it).
If you don't put a message on the command line, you will be prompted for it.
This is usually the preferable way to invoke
.I tel.
.PP
All three commands are actually the same program, and share much of the same
behavior.
.PP
Permission to write may be denied or granted by use of the
.IR mesg (1)
command.
Your write permissions upon login are installation dependent.
If you write a person who has permissions on,
but is currently writing someone else,
you will be warned of the fact and be given
a chance to cancel your write request before interupting
the other conversation.
If you write a person who is running a command under
.IR amin (1)
you will be warned similarly.
.PP
You can always send messages to people who are currently writing to you,
even if there message permissions are off.
If you have sent a person a
.I tel
message, then that person can write or telegram to you for the next 4 minutes,
even if your message permissions are off.
This means that you won't be sitting around wondering why someone won't
reply, just because you've forgotten to turn your permissions on.
It also means that if you don't want someone to be able to talk to you, then
you shouldn't talk to them.
Root may write anyone.
.PP
If you invoke the
.I write
or
.I ojot
command with no user name,
they will write to whatever user is currently writing you.
If no one is writing you, an error message is printed.
.PP
If you invoke the
.IR write ,
.IR ojot ,
or
.I tel
command with the user name '.',
they will write again to whoever you wrote to last.
If you haven't written to anyone in this login session,
an error message is printed.
This is especially useful when you are exchanging a series of messages back
and forth with
.IR tel .
.PP
If you want to write to a user who is logged in more than once,
the tty argument may be used to indicate the appropriate terminal.
If the tty argument is not given,
the terminal from which you are being written will be written to,
if there is one.  If not, one of the lines you have write permission to
will be chosen.
If the tty argument is given, the user name can be given as "-", in which
case it will write to whomever is on that tty, if anyone is.
.PP
On some systems there may be users designated as ``helpers''.
If your system has helpers, then doing ``write help'' will write to some
helper who is not busy.
If more than one helper is available, one is
selected at random to distribute the workload.
Helpers designate themselves with the
.IR mesg (1)
command.
They are considered busy if they are writing someone else, or if they
are running a command under the
.IR amin (1)
program.
.PP
If the character ! , | , or & is found at the beginning of a line,
.I write
calls the shell to execute the rest of the line as a unix command.
If the command began with a ! the output of the command
will be sent only to your terminal.
If it began with a |, output will be sent only to the other person's terminal.
If it began with a & each of you will recieve a copy of the output.
Note that
.I write
expands all strange control characters before sending them
to the other person's terminal,
but does not do so for characters echoed back to your terminal.
.PP
.I Write
provides several command line options.
Actually, the only difference between
.IR write ,
.IR ojot ,
and 
.I tel
is what default values they have for these options:
.TP
.B \-c
Send each character as it is typed.  Actually, it will not begin
doing so until after the other party has replied.  Also, if you type
a line starting with a ")" then the rest of the current line will be held
until you hit return and the sent (minus the ")").
When
this option used, typing a control-R
will reprint the text of the line you are currently typing,
and control-W will erase the last word you typed,
even if your unix system doesn't usually support these.
In the
.I ojot
command this is the default.
.TP
.B \-l
Send no characters until a full line has been entered.
In the
.I write
command this is the default.
.TP
.B \-n
During the duration of this conversation,
temporarily turn off your message permissions,
so as not to allow people other than the
person being writen to write you.
.TP
.B \-y
During the duration of this conversation, temporarily turn on your message
permissions,
allowing other people to write you after warning them that you are
writing someone else.
.TP
.B \-p
Postpone the receipt of telegrams 
during the duration of the conversation.
All telegram received during the conversation
will be saved in your .lastmesg file,
and will be displayed when you are finished.
The
.IR huh (1)
command can be used in a shell escape to check saved messages without leaving
.IR write .
.TP
.B \-s
During the duration of this conversation,
leave your write permissions unchanged.
This normally the default.
.TP
.B \-r
This causes
.I write
to prompt for the root passwd.
If it is given correctly, you will be able to write anyone, no matter how
his message permissions are set, amd you can override his preference for
.I write
or
.IR tel .
.TP
.B \-f
Disallow piping input through
.I write
and disable the '&' and '|' shell escapes.
This is mostly meant to be used on 'options' commands in the orville.conf file.
It has been mostly obsoleted by the 'pipes' configuration command.
.TP
.B \-t
Sends a one line message (called a telegram) and then disconnects immediately.
The text of the message may be given on the command line, or, if it isn't,
you will be prompted for it.
Though write will attempt to blank out messages given on the command line
so they cannot be seen by users running
.IR w (1)
or 
.IR ps (1),
this will not always work, so secret messages should not be placed on the
command line.
This is the default in the
.I tel
command.
.TP
.B \-S
Normally if you send a telegram to someone who has indicated a preference
for writes, you get asked if you want to switch to writing, and vice versa.
The -S flag suppresses this question, and just makes it quietly fail
(unless you are root, in which case it quietly succeeds).
.TP
.B \-v
print the version number.
.PP
The options selected by the writer may in some cases be overridden by the
recipient.
You can set your preferences for writes versus telegrams,
and for line mode versus character mode with the
.IR mesg (1)
command.
If the recipient has set write/telegram
preferences, you will be asked if you want to use the other if you write
him the wrong way.
If you invoke
.I Write
with a
.B \-S
flag, then you will not be asked if you want to switch.
Only root can actually override the recipient's preferences.
For regular users, if you decline to switch, the command fails.
.PP
If the recipient has set character/line mode preferences,
a message will be printed and
you will be forced into his or her prefered mode.
.SH CONFIGURATION
The
.I orville.conf
file contains configuration information for Orville write and the associated
utilities.  Lines starting with '#' and blank lines are ignored.  Other lines
contain the commands listed below:
.IP "answertel <seconds>" 1i
Normally you can send telegrams to a person for four minutes (240 seconds)
after they sent you a telegram, even if their message permissions are off.
This command can be used to set size of that window to other values.
.IP "disconnect [y|n]" 1i
If disconnect is enabled the 'mesg d' and 'mesg N' commands
can be used by the writee
to disconnect everyone currently writing them.  (See
.IR mesg (1)).
It is enabled by default.
.IP "exceptions [y|n]" 1i
If exceptions are enabled the 'mesg ye' and 'mesg ne' commandsa
can be used to limit which particular users can and cannot write you (See
.IR mesg (1)).
It is enabled by default.
.IP "fromhost [y|n]" 1i
If this flag is set, then message announcement banners will include the
hostname of the sender's machine (and the reciever's since write does
not allow interhost communications).
It is disabled by default.
.IP "helperlist <path>" 1i
If this flag is set, then only people whose logins appear in the given file
may be helpers.  Otherwise, anyone may be.
It is disabled by default.
.IP "helpername <name>" 1i
By default you get help by doing 'write help'.  If you want to use some 
keyword other than 'help', use this command to define it.
.IP "helpers [y|n]" 1i
Can people designate themselves to be helpers, and should 'write help'
work?  By default, no.
.IP "log <path>" 1i
What file should logging be done in?  If not defined, or if it is defined
and the file does not exist, then no logging will be done.
.IP "loglevel <num>" 1i
How much logging should be done?  Level 0 means none.  Level 1 means only
log help requests (with information about whether they succeeded or not).
Level 2 means logging a one-line description of each write connection made.
Of course, no logging is done if 'log' is not defined or does not exist.
No content of any write conversation is ever logged.
The default is 1.
.IP "nohelp <path>" 1i
If someone does 'write help', but no helpers are found, this file is displayed.
Normally it has information on other places to get help.
If not defined, nothing is printed.
.IP "pipes [y|n]" 1i
If turned off, this disallows piping data through write, so you can't do
'cat /etc/termcap | write joe'.  It also disables the '|' and '&' shell
escapes.  This may be necessary if many users are using write to annoy other
users by sending large chunks of data.
It defaults on.
.IP "novicehelp <path>" 1i
If the environment variable NOVICE is defined, then print the contents of this
file before running write.  If not defined, nothing is printed.
.IP "options <command-name> -<flags>..." 1i
Set default options for different links to the write program.  For example,
if you have the line 'options jot -c' and you make a link to the write program
named 'jot', then jot will default to character mode instead of line mode.
If command-name is '*', then all links (even ones created by users) get that
option.
.IP "wrthist <path>" 1i
This is the full pathname of the 'wrthist' file which maintains information
about user's recent messages.  It is used to limit telegram flooding attacks,
and allow replies to telegrams during the four minute window.
By default it is in the same directory as the
'orville.conf' file.
.IP "wrttmp <path>" 1i
This is the full pathname of the 'wrttmp' file which maintains information
about user's current state.  By default it is in the same directory as the
'orville.conf' file.
.SH AUTHOR
Jan Wolter
.SH "SEE ALSO"
mail(1), mesg(1), who(1), huh(1), finger(1), amin(1), helpers(1).