WRITE(1) User Commands WRITE(1)

NAME

write - write to another user

SYNOPSIS

write user [terminal]

DESCRIPTION

The write utility reads lines from the user's standard input and writes
them to the terminal of another user. When first invoked, it writes the
message:

Message from sender-login-id (sending-terminal) [date]...


to user. When it has successfully completed the connection, the sender's
terminal will be alerted twice to indicate that what the sender is typing
is being written to the recipient's terminal.


If the recipient wants to reply, this can be accomplished by typing

write sender-login-id [sending-terminal]


upon receipt of the initial message. Whenever a line of input as
delimited by a NL, EOF, or EOL special character is accumulated while in
canonical input mode, the accumulated data will be written on the other
user's terminal. Characters are processed as follows:

o Typing the alert character will write the alert character to
the recipient's terminal.

o Typing the erase and kill characters will affect the sender's
terminal in the manner described by the termios(3C) interface.

o Typing the interrupt or end-of-file characters will cause
write to write an appropriate message (EOT\n in the C locale)
to the recipient's terminal and exit.

o Typing characters from LC_CTYPE classifications print or space
will cause those characters to be sent to the recipient's
terminal.

o When and only when the stty iexten local mode is enabled,
additional special control characters and multi-byte or
single-byte characters are processed as printable characters
if their wide character equivalents are printable.

o Typing other non-printable characters will cause them to be
written to the recipient's terminal as follows: control
characters will appear as a `^' followed by the appropriate
ASCII character, and characters with the high-order bit set
will appear in "meta" notation. For example, `\003' is
displayed as `^C' and `\372' as `M-z'.


To write to a user who is logged in more than once, the terminal argument
can be used to indicate which terminal to write to. Otherwise, the
recipient's terminal is the first writable instance of the user found in
/usr/adm/utmpx, and the following informational message will be written
to the sender's standard output, indicating which terminal was chosen:

user is logged on more than one place.
You are connected to terminal.
Other locations are:terminal


Permission to be a recipient of a write message can be denied or granted
by use of the mesg utility. However, a user's privilege may further
constrain the domain of accessibility of other users' terminals. The
write utility will fail when the user lacks the appropriate privileges to
perform the requested action.


If the character ! is found at the beginning of a line, write calls the
shell to execute the rest of the line as a command.


write runs setgid() (see setuid(2)) to the group ID tty, in order to have
write permissions on other users' terminals.


The following protocol is suggested for using write: when you first write
to another user, wait for them to write back before starting to send.
Each person should end a message with a distinctive signal (that is, (o)
for over) so that the other person knows when to reply. The signal (oo)
(for over and out) is suggested when conversation is to be terminated.

OPERANDS

The following operands are supported:

user
User (login) name of the person to whom the message will be
written. This operand must be of the form returned by the
who(1) utility.


terminal
Terminal identification in the same format provided by the
who utility.

ENVIRONMENT VARIABLES

See environ(7) for descriptions of the following environment variables
that affect the execution of write: LANG, LC_ALL, LC_CTYPE, LC_MESSAGES,
and NLSPATH.

EXIT STATUS

The following exit values are returned:

0
Successful completion.


>0
The addressed user is not logged on or the addressed user denies
permission.

FILES

/var/adm/utmpx
User and accounting information for write


/usr/bin/sh
Bourne shell executable file

ATTRIBUTES

See attributes(7) for descriptions of the following attributes:


+--------------------+-------------------+
| ATTRIBUTE TYPE | ATTRIBUTE VALUE |
+--------------------+-------------------+
|CSI | Enabled |
+--------------------+-------------------+
|Interface Stability | Committed |
+--------------------+-------------------+
|Standard | See standards(7). |
+--------------------+-------------------+

SEE ALSO

mail(1), mesg(1), pr(1), sh(1), talk(1), who(1), setuid(2), termios(3C),
attributes(7), environ(7), standards(7)

DIAGNOSTICS

user is not logged on

The person you are trying to write to is not logged on.


Permission denied

The person you are trying to write to denies that permission (with
mesg).


Warning: cannot respond, set mesg-y

Your terminal is set to mesg n and the recipient cannot respond to
you.


Can no longer write to user

The recipient has denied permission (mesg n) after you had started
writing.


November 3, 2000 WRITE(1)