Man Pages

write(1p) - phpMan write(1p) - phpMan

Command: man perldoc info search(apropos)  


WRITE(1P)                  POSIX Programmer's Manual                 WRITE(1P)



PROLOG
       This manual page is part of the POSIX Programmer's Manual.  The Linux implementation of this interface may dif-
       fer (consult the corresponding Linux manual page for details of Linux behavior), or the interface  may  not  be
       implemented on Linux.

NAME
       write - write to another user

SYNOPSIS
       write user_name [terminal]

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


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

       to user_name. When it has successfully completed the connection, the sender's terminal shall 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 an NL, EOF, or EOL special char-
       acter (see the Base Definitions volume of IEEE Std 1003.1-2001, Chapter  11,  General  Terminal  Interface)  is
       accumulated  while in canonical input mode, the accumulated data shall be written on the other user's terminal.
       Characters shall be processed as follows:

        * Typing <alert> shall write the alert character to the recipient's terminal.


        * Typing the erase and kill characters shall affect the sender's terminal  in  the  manner  described  by  the
          termios  interface  in  the  Base  Definitions  volume of IEEE Std 1003.1-2001, Chapter 11, General Terminal
          Interface.


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


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


        * When and only when the stty iexten local mode is enabled, the existence and processing of additional special
          control characters and multi-byte or single-byte functions is implementation-defined.


        * Typing  other  non-printable characters shall cause implementation-defined sequences of printable characters
          to be written to the recipient's terminal.


       To write to a user who is logged in more than once, the terminal argument can be used to indicate which  termi-
       nal  to  write  to;  otherwise, the recipient's terminal is selected in an implementation-defined manner and an
       informational message is written to the sender's standard output, indicating which terminal was chosen.

       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
       shall fail when the user lacks the appropriate privileges to perform the requested action.

OPTIONS
       None.

OPERANDS
       The following operands shall be supported:

       user_name
              Login name of the person to whom the message shall be written. The application shall  ensure  that  this
              operand is of the form returned by the who utility.

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


STDIN
       Lines to be copied to the recipient's terminal are read from standard input.

INPUT FILES
       None.

ENVIRONMENT VARIABLES
       The following environment variables shall affect the execution of write:

       LANG   Provide  a  default  value  for the internationalization variables that are unset or null. (See the Base
              Definitions volume of IEEE Std 1003.1-2001, Section 8.2, Internationalization Variables for  the  prece-
              dence of internationalization variables used to determine the values of locale categories.)

       LC_ALL If set to a non-empty string value, override the values of all the other internationalization variables.

       LC_CTYPE
              Determine the locale for the interpretation of sequences of bytes of text data as characters (for  exam-
              ple,  single-byte  as opposed to multi-byte characters in arguments and input files). If the recipient's
              locale does not use an LC_CTYPE equivalent to the sender's, the results are undefined.

       LC_MESSAGES
              Determine the locale that should be used to affect the format and contents of diagnostic messages  writ-
              ten to standard error and informative messages written to standard output.

       NLSPATH
              Determine the location of message catalogs for the processing of LC_MESSAGES .


ASYNCHRONOUS EVENTS
       If  an  interrupt  signal is received, write shall write an appropriate message on the recipient's terminal and
       exit with a status of zero. It shall take the standard action for all other signals.

STDOUT
       An informational message shall be written to standard output if a recipient is logged in more than once.

STDERR
       The standard error shall be used only for diagnostic messages.

OUTPUT FILES
       The recipient's terminal is used for output.

EXTENDED DESCRIPTION
       None.

EXIT STATUS
       The following exit values shall be returned:

        0     Successful completion.

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


CONSEQUENCES OF ERRORS
       Default.

       The following sections are informative.

APPLICATION USAGE
       The talk utility is considered by some users to be a more usable utility on full-screen terminals.

EXAMPLES
       None.

RATIONALE
       The write utility was included in this volume of IEEE Std 1003.1-2001 since it can be implemented on all termi-
       nal  types.  The standard developers considered the talk utility, which cannot be implemented on certain termi-
       nals, to be a "better" communications interface. Both of these programs are in  widespread  use  on  historical
       implementations. Therefore, the standard developers decided that both utilities should be specified.

       The  format  of the terminal name is unspecified, but the descriptions of ps, talk, who, and write require that
       they all use or accept the same format.

FUTURE DIRECTIONS
       None.

SEE ALSO
       mesg, talk, who, the Base Definitions volume of IEEE Std 1003.1-2001, Chapter 11, General Terminal Interface

COPYRIGHT
       Portions of this text are reprinted and reproduced in electronic form from IEEE Std 1003.1, 2003 Edition, Stan-
       dard  for Information Technology -- Portable Operating System Interface (POSIX), The Open Group Base Specifica-
       tions Issue 6, Copyright (C) 2001-2003 by the Institute of Electrical and Electronics Engineers,  Inc  and  The
       Open Group. In the event of any discrepancy between this version and the original IEEE and The Open Group Stan-
       dard, the original IEEE and The Open Group Standard is the referee  document.  The  original  Standard  can  be
       obtained online at http://www.opengroup.org/unix/online.html .



IEEE/The Open Group                  2003                            WRITE(1P)