TPUT(P) POSIX Programmer's Manual TPUT(P)NAMEtput - change terminal characteristics
SYNOPSIStput [-T type] operand...
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.
OPTIONS
The tput utility shall conform to the Base Definitions volume of
IEEE Std 1003.1-2001, 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 .
OPERANDS
The following strings shall be supported as operands by the implementa‐
tion 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.
STDIN
Not used.
INPUT FILES
None.
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
IEEE Std 1003.1-2001, Section 8.2, Internationalization Vari‐
ables 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.
ASYNCHRONOUS EVENTS
Default.
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.
STDERR
The standard error shall be used only for diagnostic messages.
OUTPUT FILES
None.
EXTENDED DESCRIPTION
None.
EXIT STATUS
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.
CONSEQUENCES OF ERRORS
If one of the operands is not available for the terminal, tput contin‐
ues processing the remaining operands.
The following sections are informative.
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 ini‐
tialization 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
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
RATIONALE
The list of operands was reduced to a minimum for the following rea‐
sons:
* 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 IEEE Std 1003.1-2001 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 gen‐
eral, 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.
FUTURE DIRECTIONS
None.
SEE ALSO
stty , tabs
COPYRIGHT
Portions of this text are reprinted and reproduced in electronic form
from IEEE Std 1003.1, 2003 Edition, Standard for Information Technology
-- Portable Operating System Interface (POSIX), The Open Group Base
Specifications 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 Standard, 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 TPUT(P)
