изменить характеристики терминала (change terminal characteristics)
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)
tput — change terminal characteristics
Синопсис (Synopsis)
tput [-T type] operand...
Описание (Description)
The tput utility shall display terminal-dependent information.
The manner in which this information is retrieved is unspecified.
The information displayed shall clear the terminal screen,
initialize the user's terminal, or reset the user's terminal,
depending on the operand given. The exact consequences of
displaying this information are unspecified.
Параметры (Options)
The tput utility shall conform to the Base Definitions volume of
POSIX.1‐2017, Section 12.2, Utility Syntax Guidelines.
The following option shall be supported:
-T type Indicate the type of terminal. If this option is not
supplied and the TERM variable is unset or null, an
unspecified default terminal type shall be used. The
setting of type shall take precedence over the value in
TERM.
Операнды (Operands)
The following strings shall be supported as operands by the
implementation in the POSIX locale:
clear Display the clear-screen sequence.
init Display the sequence that initializes the user's
terminal in an implementation-defined manner.
reset Display the sequence that resets the user's terminal in
an implementation-defined manner.
If a terminal does not support any of the operations described by
these operands, this shall not be considered an error condition.
Стандартный ввод (Stdin)
Not used.
Входные файлы (Input files)
None.
Переменные окружения (Environment variables)
The following environment variables shall affect the execution of
tput:
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.
TERM Determine the terminal type. If this variable is unset
or null, and if the -T option is not specified, an
unspecified default terminal type shall be used.
Асинхронные события (Asynchronous events)
Default.
Стандартный вывод (Stdout)
If standard output is a terminal device, it may be used for
writing the appropriate sequence to clear the screen or reset or
initialize the terminal. If standard output is not a terminal
device, undefined results occur.
Стандартный вывод сообщений (Stderr)
The standard error shall be used only for diagnostic messages.
Выходные файлы (Output files)
None.
Расширенное описание (Extended description)
None.
Статус выхода (Exit)
The following exit values shall be returned:
0 The requested string was written successfully.
1 Unspecified.
2 Usage error.
3 No information is available about the specified terminal
type.
4 The specified operand is invalid.
>4 An error occurred.
Последствия ошибок (Consequences of errors)
If one of the operands is not available for the terminal, tput
continues processing the remaining operands.
The following sections are informative.
Использование в приложениях (Application usage)
The difference between resetting and initializing a terminal is
left unspecified, as they vary greatly based on hardware types.
In general, resetting is a more severe action.
Some terminals use control characters to perform the stated
functions, and on such terminals it might make sense to use tput
to store the initialization strings in a file or environment
variable for later use. However, because other terminals might
rely on system calls to do this work, the standard output cannot
be used in a portable manner, such as the following non-portable
constructs:
ClearVar=`tput clear`
tput reset | mailx -s "Wake Up" ddg
Примеры (Examples)
1. Initialize the terminal according to the type of terminal in
the environmental variable TERM. This command can be
included in a .profile file.
tput init
2. Reset a 450 terminal.
tput -T 450 reset
Обоснование (Rationale)
The list of operands was reduced to a minimum for the following
reasons:
* The only features chosen were those that were likely to be
used by human users interacting with a terminal.
* Specifying the full terminfo set was not considered
desirable, but the standard developers did not want to select
among operands.
* This volume of POSIX.1‐2017 does not attempt to provide
applications with sophisticated terminal handling
capabilities, as that falls outside of its assigned scope and
intersects with the responsibilities of other standards
bodies.
The difference between resetting and initializing a terminal is
left unspecified as this varies greatly based on hardware types.
In general, resetting is a more severe action.
The exit status of 1 is historically reserved for finding out if
a Boolean operand is not set. Although the operands were reduced
to a minimum, the exit status of 1 should still be reserved for
the Boolean operands, for those sites that wish to support them.
Будущие направления (Future directions)
None.
Смотри также (See also)
stty(1p), tabs(1p)
The Base Definitions volume of POSIX.1‐2017, Chapter 8,
Environment Variables, Section 12.2, Utility Syntax Guidelines
