написать другому пользователю (write to another user)
Пролог (Prolog)
This manual page is part of the POSIX Programmer's Manual. The
Linux implementation of this interface may differ (consult the
corresponding Linux manual page for details of Linux behavior),
or the interface may not be implemented on Linux.
Имя (Name)
write — write to another user
Синопсис (Synopsis)
write user_name [terminal]
Описание (Description)
The write utility shall read lines from the standard input and
write them to the terminal of the specified 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 character (see the Base
Definitions volume of POSIX.1‐2017, 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 POSIX.1‐2017,
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 terminal 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
appropriate privileges to perform the requested action.
Параметры (Options)
None.
Операнды (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.
Стандартный ввод (Stdin)
Lines to be copied to the recipient's terminal are read from
standard input.
Входные файлы (Input files)
None.
Переменные окружения (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 POSIX.1‐2017, Section 8.2,
Internationalization Variables for the precedence 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
example, 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 written to
standard error and informative messages written to
standard output.
NLSPATH Determine the location of message catalogs for the
processing of LC_MESSAGES.
Асинхронные события (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.
Стандартный вывод (Stdout)
An informational message shall be written to standard output if a
recipient is logged in more than once.
Стандартный вывод сообщений (Stderr)
The standard error shall be used only for diagnostic messages.
Выходные файлы (Output files)
The recipient's terminal is used for output.
Расширенное описание (Extended description)
None.
Статус выхода (Exit)
The following exit values shall be returned:
0 Successful completion.
>0 The addressed user is not logged on or the addressed user
denies permission.
Последствия ошибок (Consequences of errors)
Default.
The following sections are informative.
Использование в приложениях (Application usage)
The talk utility is considered by some users to be a more usable
utility on full-screen terminals.
Примеры (Examples)
None.
Обоснование (Rationale)
The write utility was included in this volume of POSIX.1‐2017
since it can be implemented on all terminal types. The standard
developers considered the talk utility, which cannot be
implemented on certain terminals, 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.
Будущие направления (Future directions)
None.
Смотри также (See also)
mesg(1p), talk(1p), who(1p)
The Base Definitions volume of POSIX.1‐2017, Chapter 8,
Environment Variables, Chapter 11, General Terminal Interface
