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   tee.1p    ( 1 )

дублировать стандартный ввод (duplicate standard input)

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)

tee — duplicate standard input


Синопсис (Synopsis)

tee [-ai] [file...]


Описание (Description)

The tee utility shall copy standard input to standard output, making a copy in zero or more files. The tee utility shall not buffer output.

If the -a option is not specified, output files shall be written (see Section 1.1.1.4, File Read, Write, and Creation.


Параметры (Options)

The tee utility shall conform to the Base Definitions volume of
       POSIX.1‐2017, Section 12.2, Utility Syntax Guidelines.

The following options shall be supported:

-a Append the output to the files.

-i Ignore the SIGINT signal.


Операнды (Operands)

The following operands shall be supported:

file A pathname of an output file. If a file operand is '-', it shall refer to a file named -; implementations shall not treat it as meaning standard output. Processing of at least 13 file operands shall be supported.


Стандартный ввод (Stdin)

The standard input can be of any type.


Входные файлы (Input files)

None.


Переменные окружения (Environment variables)

The following environment variables shall affect the execution of tee:

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).

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

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


Асинхронные события (Asynchronous events)

Default, except that if the -i option was specified, SIGINT shall be ignored.


Стандартный вывод (Stdout)

The standard output shall be a copy of the standard input.


Стандартный вывод сообщений (Stderr)

The standard error shall be used only for diagnostic messages.


Выходные файлы (Output files)

If any file operands are specified, the standard input shall be copied to each named file.


Расширенное описание (Extended description)

None.


Статус выхода (Exit)

The following exit values shall be returned:

0 The standard input was successfully copied to all output files.

>0 An error occurred.


Последствия ошибок (Consequences of errors)

If a write to any successfully opened file operand fails, writes to other successfully opened file operands and standard output shall continue, but the exit status shall be non-zero. Otherwise, the default actions specified in Section 1.4, Utility Description Defaults apply.

The following sections are informative.


Использование в приложениях (Application usage)

The tee utility is usually used in a pipeline, to make a copy of the output of some utility.

The file operand is technically optional, but tee is no more useful than cat when none is specified.


Примеры (Examples)

Save an unsorted intermediate form of the data in a pipeline:

... | tee unsorted | sort > sorted


Обоснование (Rationale)

The buffering requirement means that tee is not allowed to use ISO C standard fully buffered or line-buffered writes. It does not mean that tee has to do 1-byte reads followed by 1-byte writes.

It should be noted that early versions of BSD ignore any invalid options and accept a single '-' as an alternative to -i. They also print a message if unable to open a file:

"tee: cannot access %s\n", <pathname>

Historical implementations ignore write errors. This is explicitly not permitted by this volume of POSIX.1‐2017.

Some historical implementations use O_APPEND when providing append mode; others use the lseek() function to seek to the end- of-file after opening the file without O_APPEND. This volume of POSIX.1‐2017 requires functionality equivalent to using O_APPEND; see Section 1.1.1.4, File Read, Write, and Creation.


Будущие направления (Future directions)

None.


Смотри также (See also)

Chapter 1, Introduction, cat(1p)

The Base Definitions volume of POSIX.1‐2017, Chapter 8, Environment Variables, Section 12.2, Utility Syntax Guidelines

The System Interfaces volume of POSIX.1‐2017, lseek(3p)