Provided by: ncurses-bin_6.4+20240113-1ubuntu2_amd64 
NAME
tput, init, reset - initialize a terminal, exercise its capabilities, or query terminfo
database
SYNOPSIS
tput [-T terminal-type] {cap-code [parameter ...]} ...
tput [-T terminal-type] [-x] clear
tput [-T terminal-type] init
tput [-T terminal-type] reset
tput [-T terminal-type] longname
tput -S
tput -V
DESCRIPTION
tput uses the terminfo library and database to make terminal-specific capabilities and
information available to the shell, to initialize or reset the terminal, or to report a
description of the current (or specified) terminal type. Terminal capabilities are
accessed by cap-code.
terminfo(5) discusses terminal capabilities at length and presents a complete list of cap-
codes.
When retrieving capability values, the result depends upon the capability's type.
Boolean tput sets its exit status to 0 if the terminal possesses cap-code, and 1 if it
does not.
numeric tput writes cap-code's decimal value to the standard output stream if defined (-1
if it is not) followed by a newline.
string tput writes cap-code's value to the standard output stream if defined, without a
trailing newline.
Before using a value returned on the standard output, the application should test tput's
exit status to be sure it is 0; see section “EXIT STATUS” below.
Operands
Generally, an operand is a cap-code, a capability code from the terminal database, or a
parameter thereto. Three others are specially recognized by tput: init, reset, and
longname. Although these resemble capability codes, they in fact receive special
handling; we term them “pseudo-capabilities”.
cap-code indicates a capability from the terminal database.
If the capability is of string type and takes parameters, the arguments
following the capability will be used as its parameters.
Most parameters are numeric. Only a few terminal capabilities require string
parameters; tput uses a table to decide which to pass as strings. Normally
tput uses tparm(3NCURSES) to perform the substitution. If no parameters are
given for the capability, tput writes the string without performing the
substitution.
init initializes the terminal. If the terminal database is present and an entry for
the user's terminal type exists, the following occur.
(1) tput retrieves the terminal's mode settings. It successively tests the
file descriptors corresponding to
• the standard error stream,
• the standard output stream,
• the standard input stream, and
• /dev/tty
to obtain terminal settings. Having retrieved them, tput remembers which
descriptor to use for further updates.
(2) If the terminal dimensions cannot be obtained from the operating system,
but the environment or terminal type database entry describes them, tput
updates the operating system's notion of them.
(3) tput updates the terminal modes.
• Any delays specified in the entry (for example, when a newline is
sent) are set in the terminal driver.
• Tab expansion is turned on or off per the specification in the entry,
and
• if tabs are not expanded, standard tabs (every 8 spaces) are set.
(4) If initialization capabilities, detailed in subsection “Tabs and
Initialization” of terminfo(5), are present, tput writes them to the
standard output stream.
(5) tput flushes the standard output stream.
If an entry lacks the information needed for an activity above, that activity
is silently skipped.
reset re-initializes the terminal. A reset differs from initialization in two ways.
(1) tput sets the the terminal modes to a “sane” state,
• enabling cooked and echo modes,
• disabling cbreak and raw modes,
• enabling newline translation, and
• setting any unset special characters to their default values.
(2) If any reset capabilities are defined for the terminal type, tput writes
them to the output stream. Otherwise, tput uses any defined
initialization capabilities. Reset capabilities are detailed in
subsection “Tabs and Initialization” of terminfo(5).
longname A terminfo entry begins with one or more names by which an application can
refer to the entry, before the list of terminal capabilities. The names are
separated by “|” characters. X/Open Curses terms the last name the “long
name”, and indicates that it may include blanks.
tic warns if the last name does not include blanks, to accommodate old terminfo
entries that treated the long name as an optional feature. The long name is
often referred to as the description field.
If the terminal database is present and an entry for the user's terminal type
exists, tput reports its description to the standard output stream, without a
trailing newline. See terminfo(5).
Note: Redirecting the output of “tput init” or “tput reset” to a file will capture only
part of their actions. Changes to the terminal modes are not affected by file descriptor
redirection, since the terminal modes are altered via ioctl(2).
Aliases
If tput is invoked via link with any of the names clear, init, or reset, it operates as if
run with the corresponding (pseudo-)capability operand. For example, executing a link
named reset that points to tput has the same effect as “tput reset”. (The tset(1) utility
also treats a link named reset specially.)
If tput is invoked by a link named init, this has the same effect as “tput init”. Such a
link is seldom employed because another program of that name is in widespread use.
Terminal Size
Besides the pseudo-capabilities (such as init), tput treats the lines and cols cap-codes
specially: it may call setupterm(3NCURSES) to obtain the terminal size.
• First, tput attempts to obtain these capabilities from the terminal database. This
generally fails for terminal emulators, which lack a fixed window size and thus omit
the capabilities.
• It then asks the operating system for the terminal's size, which generally works,
unless the connection is via a serial line that 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, ultimately, the terminal
database).
OPTIONS
-S retrieves more than one capability per invocation of tput. The capabilities must
be passed to tput from the standard input stream instead of from the command line
(see section “EXAMPLES” below). Only one cap-code is allowed per line. The -S
option changes the meanings of the 0 and 1 exit statuses (see section “EXIT
STATUS” below).
Some capabilities use string parameters rather than numeric ones. tput employs a
built-in table and the presence of parameters in its input to decide how to
interpret them, and whether to use tparm(3NCURSES).
-T type indicates the terminal's type. Normally this option is unnecessary, because a
default is taken from the TERM environment variable. If specified, the
environment variables LINES and COLUMNS are also ignored.
-V reports the version of ncurses associated with tput, and exits with a successful
status.
-x prevents “tput clear” from attempting to clear the scrollback buffer.
EXIT STATUS
Normally, one should interpret tput's exit statuses as follows.
Status Meaning When -S Not Specified
───────────────────────────────────────────────────────────────────────────────────────────
0 Boolean or string capability present
1 Boolean or numeric capability absent
2 usage error or no terminal type specified
3 unrecognized terminal type
4 unrecognized capability code
>4 system error (4 + errno)
When the -S option is used, some statuses change meanings.
Status Meaning When -S Specified
───────────────────────────────────────────────────────────────────────────────────────────
0 all operands interpreted
1 unused
4 some operands not interpreted
ENVIRONMENT
tput command reads one environment variable.
TERM denotes the terminal type. Each terminal type is distinct, though many are
similar. The -T option overrides its value.
FILES
/usr/share/tabset
tab stop initialization database
/etc/terminfo
compiled terminal description database
PORTABILITY
Over time ncurses tput has differed from that of System V in two important respects, one
now mostly historical.
• “tput cap-code” writes to the standard output, which need not be a terminal device.
However, the operands that manipulate terminal modes might not use the standard
output.
System V tput's init and reset operands use logic from 4.1cBSD tset, manipulating
terminal modes. It checks the same file descriptors (and /dev/tty) for association
with a terminal device as ncurses now does, and if none are, finally assumes a 1200
baud terminal. When updating terminal modes, it ignores errors.
Until ncurses 6.1 (see section “HISTORY” below), tput did not modify terminal modes.
It now employs a scheme similar to System V, using functions shared with tset (and
ultimately based on 4.4BSD tset). If it is not able to open a terminal (for instance,
when run by cron(1)), tput exits with an error status.
• System V tput assumes that the type of a cap-code operand is numeric if all the
characters of its value are decimal numbers; if they are not, it treats cap-code as a
string capability.
Most implementations that provide support for cap-code operands use the
tparm(3NCURSES) function to expand its parameters. That function expects a mixture of
numeric and string parameters, requiring tput to know which type to use.
ncurses tput uses a table to determine the parameter types for the standard cap-code
operands, and an internal function to analyze nonstandard cap-code operands.
While more reliable than System V'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, and modified it to interpret
multiple cap-codes (and parameters) on the command line. Portable applications should
not rely upon this feature; ncurses offers it to support applications written
specifically for OpenBSD.
This implementation, unlike others, accepts both termcap and terminfo cap-codes if termcap
support is compiled in. In that case, however, the predefined termcap and terminfo codes
have two ambiguities; ncurses assumes the terminfo code.
• The cap-code dl means delete_line to termcap but parm_delete_line to terminfo.
termcap uses the code DL for parm_delete_line. terminfo uses the code dch1 for
delete_line.
• The cap-code ed means exit_delete_mode to termcap but clr_eos to terminfo. termcap
uses the code cd for clr_eos. terminfo uses the code rmdc for exit_delete_mode.
The longname operand, -S option, and the parameter-substitution features used in the cup
example below, were not supported in AT&T/USL curses before SVr4 (1989). Later, 4.3BSD-
Reno (1990) added support for longname, and in 1994, NetBSD added support for the
parameter-substitution features.
IEEE Std 1003.1/The Open Group Base Specifications Issue 7 (POSIX.1-2008) documents only
the clear, init, and reset operands. A few observations of interest arise from that
selection.
• ncurses supports clear as it does any other standard cap-code. The others (init and
longname) do not correspond to terminal capabilities.
• The tput on SVr4-based systems such as Solaris, IRIX64, and HP-UX, as well as others
such as AIX and Tru64, also support standard cap-code 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 ncurses tput, configured for both terminfo (tested
first) and termcap (as a fallback).
Because (apparently) all certified Unix systems support the full set of capability codes,
the reason for documenting only a few may not be apparent.
• X/Open Curses Issue 7 documents tput differently, with cap-code 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 capability database.
• While it is certainly possible to write a tput program without using curses, no system
with a curses implementation provides a tput utility that does not also support
standard cap-codes.
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 (that is, System V curses
behavior).
• It assigns exit status 4 to “invalid operand”, which may have the same meaning as
“unknown capability”. For instance, the source code for Solaris xcurses uses the term
“invalid” in this case.
• It assigns exit status 255 to a numeric variable that is not specified in the terminfo
database. That likely is a documentation error, mistaking the “-1” written to the
standard output to indicate an absent or cancelled numeric capability for an
(unsigned) exit status.
The various System V implementations (AIX, HP-UX, Solaris) use the same exit statuses as
ncurses.
NetBSD curses documents exit statuses that correspond to neither ncurses nor X/Open
Curses.
HISTORY
Bill Joy wrote a tput command during development of 4BSD in October 1980. This initial
version only cleared the screen, and did not ship with official distributions.
System V developed a different tput command.
• SVr2 (1984) provided a rudimentary tput that checked the parameter against each
predefined capability and returned the corresponding value. This version of tput did
not use tparm(3NCURSES) for parameterized capabilities.
• SVr3 (1987) replaced that with a more extensive program whose support for init and
reset operands (more than half the program) incorporated the reset feature of BSD tset
written by Eric Allman.
• SVr4 (1989) added color initialization by using the orig_colors (oc) and orig_pair
(op) capabilities in its init logic.
Keith Bostic refactored BSD tput for shipment in 4.3BSD-Tahoe (1988), then replaced it the
next year with a new implementation based on System V tput. Bostic's version similarly
accepted some parameters named for terminfo (pseudo-)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 modes as the
earlier BSD tset had done.
At the same time, Bostic added a shell script named “clear” that used tput to clear the
screen. Both of these appeared in 4.4BSD, becoming the “modern” BSD implementation of
tput.
The origin of ncurses tput lies outside both System V and BSD, in 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. Incorporating the
portions dealing with terminal capabilities almost without change, Raymond made
improvements to the way command-line parameters were handled.
Before ncurses 6.1 (2018), its tset and tput utilities differed.
• tset was more effective, resetting the terminal modes and special characters.
• On the other hand, tset's repertoire of terminal capabilities for resetting the
terminal was more limited; it had only equivalents of reset_1string (rs1),
reset_2string (rs2), and reset_file (rf), and not the tab stop and margin update
features of tput.
The reset program is traditionally an alias for tset due to its ability to reset terminal
modes and special characters.
As of ncurses 6.1, the “reset” features of the two programs are (mostly) the same. Two
minor differences remain.
• The tset program waits one second when resetting, in case the terminal happens to be a
hardware device.
• The two programs write the terminal initialization strings to different streams; that
is, standard error for tset and standard output for tput.
EXAMPLES
tput init
Initialize the terminal according to the type of terminal in the TERM environment
variable. If the system does not reliably initialize the terminal upon login, this
command can be included in $HOME/.profile after exporting the TERM environment
variable.
tput -T5620 reset
Reset an AT&T 5620 terminal, overriding the terminal type in the TERM environment
variable.
tput cnorm
Set cursor to normal visibility.
tput home
Move the cursor to row 0, column 0: the upper left corner of the screen, usually
known as the “home” cursor position.
tput clear
Clear the screen: write the clear_screen capability's value to the standard output
stream.
tput cols
Report the number of columns used by the current terminal type.
tput -Tadm3a cols
Report the number of columns used by an ADM-3A terminal.
strong=`tput smso` normal=`tput rmso`
Set shell variables to capability values: strong and normal, to begin and end,
respectively, stand-out mode for the terminal. One might use these to present a
prompt.
printf "${strong}Username:${normal} "
tput hc
Indicate via exit status whether the terminal is a hard copy device.
tput cup 23 4
Move the cursor to row 23, column 4.
tput cup
Report the value of the cursor_address (cup) capability (used for cursor movement),
with no parameters substituted.
tput longname
Report the terminfo database's description of the terminal type specified in the
TERM environment variable.
tput -S
Process multiple capabilities. The -S option can be profitably used with a shell
“here document”.
$ tput -S <<!
> clear
> cup 10 10
> bold
> !
The foregoing clears the screen, moves the cursor to position (10, 10) and turns on
bold (extra bright) mode.
tput clear cup 10 10 bold
Perform the same actions as the foregoing “tput -S” example.
SEE ALSO
clear(1), stty(1), tabs(1), tset(1), termcap(3NCURSES), terminfo(5)