tput - Man Page

initialize a terminal, exercise its capabilities, or query terminfo database

Examples (TL;DR)

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(3X) 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”.

This feature was introduced by ncurses 5.2 in 2000. It is rarely used:

clear

is a separate program, which is both smaller and more frequently executed.

init

has the same name as another program in widespread use.

reset

is provided by the tset(1) utility (also via a link named reset).

Terminal Size

Besides the pseudo-capabilities (such as init), tput treats the lines and cols cap-codes specially: it may call setupterm(3X) 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(3X).

-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.

StatusMeaning When -S Not Specified
0Boolean or string capability present
1Boolean or numeric capability absent
2usage error or no terminal type specified
3unrecognized terminal type
4unrecognized capability code
>4system error (4 + errno)

When the -S option is used, some statuses change meanings.

StatusMeaning When -S Specified
0all operands interpreted
1unused
4some operands not interpreted

Environment

tput 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

/usr/share/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.

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 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.

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 (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).

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.

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 codes 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.

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.

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 <<!clearcup 10 10bold!

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), curs_termcap(3X), terminfo(5)

Referenced By

clear(1), console_codes(4), curs_terminfo.3x(3), ksh93(1), setterm(1), tabs(1), termios(3), xterm(1).

2024-01-20 ncurses 6.4 User commands