|
HTML rendering created 2024-06-26 by Michael Kerrisk, author of The Linux Programming Interface. For details of in-depth Linux/UNIX system programming training courses that I teach, look here. Hosting by jambit GmbH. |
|
|
NAME | SYNOPSIS | DESCRIPTION | EXAMPLES | FILES | EXIT CODES | DIAGNOSTICS | HISTORY | PORTABILITY | SEE ALSO | COLOPHON |
|
|
|
@TPUT@(1) General Commands Manual @TPUT@(1)
@TPUT@, reset - initialize a terminal or query terminfo database
@TPUT@ [-Ttype] capname [parameters]
@TPUT@ [-Ttype] [-x] clear
@TPUT@ [-Ttype] init
@TPUT@ [-Ttype] reset
@TPUT@ [-Ttype] longname
@TPUT@ -S <<
@TPUT@ -V
The @TPUT@ utility uses the terminfo database to make the values
of terminal-dependent capabilities and information available to
the shell (see sh(1)), to initialize or reset the terminal, or
return the long name of the requested terminal type. The result
depends upon the capability's type:
string
@TPUT@ writes the string to the standard output. No
trailing newline is supplied.
integer
@TPUT@ writes the decimal value to the standard output,
with a trailing newline.
boolean
@TPUT@ simply sets the exit code (0 for TRUE if the
terminal has the capability, 1 for FALSE if it does not),
and writes nothing to the standard output.
Before using a value returned on the standard output, the
application should test the exit code (e.g., $?, see sh(1)) to be
sure it is 0. (See the EXIT CODES and DIAGNOSTICS sections.)
For a complete list of capabilities and the capname associated
with each, see terminfo(5).
Options
-S allows more than one capability per invocation of @TPUT@.
The capabilities must be passed to @TPUT@ from the
standard input instead of from the command line (see
example). Only one capname is allowed per line. The -S
option changes the meaning of the 0 and 1 boolean and
string exit codes (see the EXIT CODES section).
Because some capabilities may use string parameters rather
than numbers, @TPUT@ uses a table and the presence of
parameters in its input to decide whether to use
tparm(3X), and how to interpret the parameters.
-Ttype indicates the type of terminal. Normally this option is
unnecessary, because the default is taken from the
environment variable TERM. If -T is specified, then the
shell variables LINES and COLUMNS will also be ignored.
-V reports the version of ncurses which was used in this
program, and exits.
-x do not attempt to clear the terminal's scrollback buffer
using the extended “E3” capability.
Commands
A few commands (init, reset and longname) are special; they are
defined by the @TPUT@ program. The others are the names of
capabilities from the terminal database (see terminfo(5) for a
list). Although init and reset resemble capability names, @TPUT@
uses several capabilities to perform these special functions.
capname
indicates the capability from the terminal database.
If the capability is a string that takes parameters, the
arguments following the capability will be used as
parameters for the string.
Most parameters are numbers. Only a few terminal
capabilities require string parameters; @TPUT@ uses a
table to decide which to pass as strings. Normally @TPUT@
uses tparm(3X) to perform the substitution. If no
parameters are given for the capability, @TPUT@ writes the
string without performing the substitution.
init If the terminal database is present and an entry for the
user's terminal exists (see -Ttype, above), the following
will occur:
(1) first, @TPUT@ retrieves the current terminal mode
settings for your terminal. It does this by
successively testing
• the standard error,
• standard output,
• standard input and
• ultimately “/dev/tty”
to obtain terminal settings. Having retrieved these
settings, @TPUT@ remembers which file descriptor to
use when updating settings.
(2) if the window size cannot be obtained from the
operating system, but the terminal description (or
environment, e.g., LINES and COLUMNS variables
specify this), update the operating system's notion
of the window size.
(3) the terminal modes will be updated:
• any delays (e.g., newline) specified in the entry
will be set in the tty driver,
• tabs expansion will be turned on or off according
to the specification in the entry, and
• if tabs are not expanded, standard tabs will be
set (every 8 spaces).
(4) if present, the terminal's initialization strings
will be output as detailed in the terminfo(5) section
on Tabs and Initialization,
(5) output is flushed.
If an entry does not contain the information needed for
any of these activities, that activity will silently be
skipped.
reset This is similar to init, with two differences:
(1) before any other initialization, the terminal modes
will be reset to a “sane” state:
• set cooked and echo modes,
• turn off cbreak and raw modes,
• turn on newline translation and
• reset any unset special characters to their
default values
(2) Instead of putting out initialization strings, the
terminal's reset strings will be output if present
(rs1, rs2, rs3, rf). If the reset strings are not
present, but initialization strings are, the
initialization strings will be output.
Otherwise, reset acts identically to init.
longname
If the terminal database is present and an entry for the
user's terminal exists (see -Ttype above), then the long
name of the terminal will be put out. The long name is
the last name in the first line of the terminal's
description in the terminfo database [see term(5)].
Aliases
@TPUT@ handles the clear, init and reset commands specially: it
allows for the possibility that it is invoked by a link with
those names.
If @TPUT@ is invoked by a link named reset, this has the same
effect as @TPUT@ reset. The @TSET@(1) utility also treats a link
named reset specially.
Before ncurses 6.1, the two utilities were different from each
other:
• @TSET@ utility reset the terminal modes and special
characters (not done with @TPUT@).
• On the other hand, @TSET@'s repertoire of terminal
capabilities for resetting the terminal was more limited,
i.e., only reset_1string, reset_2string and reset_file in
contrast to the tab-stops and margins which are set by this
utility.
• The reset program is usually an alias for @TSET@, because of
this difference with resetting terminal modes and special
characters.
With the changes made for ncurses 6.1, the reset feature of the
two programs is (mostly) the same. A few differences remain:
• The @TSET@ program waits one second when resetting, in case
it happens to be a hardware terminal.
• The two programs write the terminal initialization strings to
different streams (i.e., the standard error for @TSET@ and
the standard output for @TPUT@).
Note: although these programs write to different streams,
redirecting their output to a file will capture only part of
their actions. The changes to the terminal modes are not
affected by redirecting the output.
If @TPUT@ is invoked by a link named init, this has the same
effect as @TPUT@ init. Again, you are less likely to use that
link because another program named init has a more well-
established use.
Terminal Size
Besides the special commands (e.g., clear), @TPUT@ treats certain
terminfo capabilities specially: lines and cols. @TPUT@ calls
setupterm(3X) to obtain the terminal size:
• first, it gets the size from the terminal database (which
generally is not provided for terminal emulators which do not
have a fixed window size)
• then it asks the operating system for the terminal's size
(which generally works, unless connecting via a serial line
which does not support NAWS: negotiations about window size).
• finally, it inspects the environment variables LINES and
COLUMNS which may override the terminal size.
If the -T option is given @TPUT@ ignores the environment
variables by calling use_tioctl(TRUE), relying upon the operating
system (or finally, the terminal database).
@TPUT@ init
Initialize the terminal according to the type of terminal in
the environmental variable TERM. This command should be
included in everyone's .profile after the environmental
variable TERM has been exported, as illustrated on the
profile(5) manual page.
@TPUT@ -T5620 reset
Reset an AT&T 5620 terminal, overriding the type of terminal
in the environmental variable TERM.
@TPUT@ cup 0 0
Send the sequence to move the cursor to row 0, column 0 (the
upper left corner of the screen, usually known as the “home”
cursor position).
@TPUT@ clear
Echo the clear-screen sequence for the current terminal.
@TPUT@ cols
Print the number of columns for the current terminal.
@TPUT@ -T450 cols
Print the number of columns for the 450 terminal.
bold=`@TPUT@ smso` offbold=`@TPUT@ rmso`
Set the shell variables bold, to begin stand-out mode
sequence, and offbold, to end standout mode sequence, for
the current terminal. This might be followed by a prompt:
echo "${bold}Please type in your name: ${offbold}\c"
@TPUT@ hc
Set exit code to indicate if the current terminal is a hard
copy terminal.
@TPUT@ cup 23 4
Send the sequence to move the cursor to row 23, column 4.
@TPUT@ cup
Send the terminfo string for cursor-movement, with no
parameters substituted.
@TPUT@ longname
Print the long name from the terminfo database for the type
of terminal specified in the environmental variable TERM.
@TPUT@ -S <<!
> clear
> cup 10 10
> bold
> !
This example shows @TPUT@ processing several capabilities in
one invocation. It clears the screen, moves the cursor to
position 10, 10 and turns on bold (extra bright) mode. The
list is terminated by an exclamation mark (!) on a line by
itself.
@TERMINFO@
compiled terminal description database
@DATADIR@/tabset/*
tab settings for some terminals, in a format appropriate
to be output to the terminal (escape sequences that set
margins and tabs); for more information, see the Tabs and
Initialization, section of terminfo(5)
If the -S option is used, @TPUT@ checks for errors from each
line, and if any errors are found, will set the exit code to 4
plus the number of lines with errors. If no errors are found,
the exit code is 0. No indication of which line failed can be
given so exit code 1 will never appear. Exit codes 2, 3, and 4
retain their usual interpretation. If the -S option is not used,
the exit code depends on the type of capname:
boolean
a value of 0 is set for TRUE and 1 for FALSE.
string a value of 0 is set if the capname is defined for this
terminal type (the value of capname is returned on
standard output); a value of 1 is set if capname is not
defined for this terminal type (nothing is written to
standard output).
integer
a value of 0 is always set, whether or not capname is
defined for this terminal type. To determine if
capname is defined for this terminal type, the user
must test the value written to standard output. A
value of -1 means that capname is not defined for this
terminal type.
other reset or init may fail to find their respective files.
In that case, the exit code is set to 4 + errno.
Any other exit code indicates an error; see the DIAGNOSTICS
section.
@TPUT@ prints the following error messages and sets the
corresponding exit codes.
exit code error message
─────────────────────────────────────────────────────────────────────
0 (capname is a numeric variable that is not specified in
the terminfo(5) database for this terminal type, e.g.
@TPUT@ -T450 lines and @TPUT@ -Thp2621 xmc)
1 no error message is printed, see the EXIT CODES section.
2 usage error
3 unknown terminal type or no terminfo database
4 unknown terminfo capability capname
>4 error occurred in -S
─────────────────────────────────────────────────────────────────────
The tput command was begun by Bill Joy in 1980. The initial
version only cleared the screen.
AT&T System V provided a different tput command:
• SVr2 provided a rudimentary tput which checked the parameter
against each predefined capability and returned the
corresponding value. This version of tput did not use
tparm(3X) for the capabilities which are parameterized.
• SVr3 replaced that, a year later, by a more extensive program
whose init and reset subcommands (more than half the program)
were incorporated from the reset feature of BSD tset written
by Eric Allman.
• SVr4 added color initialization using the orig_colors and
orig_pair capabilities in the init subcommand.
Keith Bostic replaced the BSD tput command in 1989 with a new
implementation based on the AT&T System V program tput. Like the
AT&T program, Bostic's version accepted some parameters named for
terminfo capabilities (clear, init, longname and reset). However
(because he had only termcap available), it accepted termcap
names for other capabilities. Also, Bostic's BSD tput did not
modify the terminal I/O modes as the earlier BSD tset had done.
At the same time, Bostic added a shell script named “clear”,
which used tput to clear the screen.
Both of these appeared in 4.4BSD, becoming the “modern” BSD
implementation of tput.
This implementation of tput began from a different source than
AT&T or BSD: Ross Ridge's mytinfo package, published on
comp.sources.unix in December 1992. Ridge's program made more
sophisticated use of the terminal capabilities than the BSD
program. Eric Raymond used that tput program (and other parts of
mytinfo) in ncurses in June 1995. Using the portions dealing
with terminal capabilities almost without change, Raymond made
improvements to the way the command-line parameters were handled.
This implementation of tput differs from AT&T tput in two
important areas:
• @TPUT@ capname writes to the standard output. That need not
be a regular terminal. However, the subcommands which
manipulate terminal modes may not use the standard output.
The AT&T implementation's init and reset commands use the BSD
(4.1c) tset source, which manipulates terminal modes. It
successively tries standard output, standard error, standard
input before falling back to “/dev/tty” and finally just
assumes a 1200Bd terminal. When updating terminal modes, it
ignores errors.
Until changes made after ncurses 6.0, @TPUT@ did not modify
terminal modes. @TPUT@ now uses a similar scheme, using
functions shared with @TSET@ (and ultimately based on the
4.4BSD tset). If it is not able to open a terminal, e.g.,
when running in cron(1), @TPUT@ will return an error.
• AT&T tput guesses the type of its capname operands by seeing
if all of the characters are numeric, or not.
Most implementations which provide support for capname
operands use the tparm function to expand parameters in it.
That function expects a mixture of numeric and string
parameters, requiring @TPUT@ to know which type to use.
This implementation uses a table to determine the parameter
types for the standard capname operands, and an internal
library function to analyze nonstandard capname operands.
Besides providing more reliable operation than AT&T's
utility, a portability problem is introduced by this
analysis: An OpenBSD developer adapted the internal library
function from ncurses to port NetBSD's termcap-based tput to
terminfo. That had been modified to interpret multiple
commands on a line. Portable applications should not rely
upon this feature; ncurses provides it to support
applications written specifically for OpenBSD.
This implementation (unlike others) can accept both termcap and
terminfo names for the capname feature, if termcap support is
compiled in. However, the predefined termcap and terminfo names
have two ambiguities in this case (and the terminfo name is
assumed):
• The termcap name dl corresponds to the terminfo name dl1
(delete one line).
The terminfo name dl corresponds to the termcap name DL
(delete a given number of lines).
• The termcap name ed corresponds to the terminfo name rmdc
(end delete mode).
The terminfo name ed corresponds to the termcap name cd
(clear to end of screen).
The longname and -S options, and the parameter-substitution
features used in the cup example, were not supported in BSD
curses before 4.3reno (1989) or in AT&T/USL curses before SVr4
(1988).
IEEE Std 1003.1/The Open Group Base Specifications Issue 7
(POSIX.1-2008) documents only the operands for clear, init and
reset. There are a few interesting observations to make
regarding that:
• In this implementation, clear is part of the capname support.
The others (init and longname) do not correspond to terminal
capabilities.
• Other implementations of tput on SVr4-based systems such as
Solaris, IRIX64 and HPUX as well as others such as AIX and
Tru64 provide support for capname operands.
• A few platforms such as FreeBSD recognize termcap names
rather than terminfo capability names in their respective
tput commands. Since 2010, NetBSD's tput uses terminfo
names. Before that, it (like FreeBSD) recognized termcap
names.
Beginning in 2021, FreeBSD uses the ncurses tput, configured
for both terminfo (tested first) and termcap (as a fallback).
Because (apparently) all of the certified Unix systems support
the full set of capability names, the reasoning for documenting
only a few may not be apparent.
• X/Open Curses Issue 7 documents tput differently, with
capname and the other features used in this implementation.
• That is, there are two standards for tput: POSIX (a subset)
and X/Open Curses (the full implementation). POSIX documents
a subset to avoid the complication of including X/Open Curses
and the terminal capabilities database.
• While it is certainly possible to write a tput program
without using curses, none of the systems which have a curses
implementation provide a tput utility which does not provide
the capname feature.
X/Open Curses Issue 7 (2009) is the first version to document
utilities. However that part of X/Open Curses does not follow
existing practice (i.e., Unix features documented in SVID 3):
• It assigns exit code 4 to “invalid operand”, which may be the
same as unknown capability. For instance, the source code
for Solaris' xcurses uses the term “invalid” in this case.
• It assigns exit code 255 to a numeric variable that is not
specified in the terminfo database. That likely is a
documentation error, confusing the -1 written to the standard
output for an absent or cancelled numeric value versus an
(unsigned) exit code.
The various Unix systems (AIX, HPUX, Solaris) use the same exit-
codes as ncurses.
NetBSD curses documents different exit codes which do not
correspond to either ncurses or X/Open.
@CLEAR@(1), stty(1), @TABS@(1), @TSET@(1), curs_termcap(3X),
terminfo(5).
This describes ncurses version @NCURSES_MAJOR@.@NCURSES_MINOR@
(patch @NCURSES_PATCH@).
This page is part of the ncurses (new curses) project.
Information about the project can be found at
⟨https://www.gnu.org/software/ncurses/ncurses.html⟩. If you have
a bug report for this manual page, send it to
[email protected]. This page was obtained from the
project's upstream Git mirror of the CVS repository
⟨https://github.com/mirror/ncurses.git⟩ on 2024-06-14. (At that
time, the date of the most recent commit that was found in the
repository was 2023-03-12.) If you discover any rendering
problems in this HTML version of the page, or you believe there
is a better or more up-to-date source for the page, or you have
corrections or improvements to the information in this COLOPHON
(which is not part of the original manual page), send a mail to
[email protected]
@TPUT@(1)
Pages that refer to this page: setterm(1), termios(3), console_codes(4), termio(7)
|
HTML rendering created 2024-06-26 by Michael Kerrisk, author of The Linux Programming Interface. For details of in-depth Linux/UNIX system programming training courses that I teach, look here. Hosting by jambit GmbH. |
|