path: root/upstream/debian-unstable/man1/tput.1

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.\" $Id: tput.1,v 1.102 2024/01/13 22:47:16 tom Exp $
.TH tput 1 2024-01-13 "ncurses 6.4" "User commands"
.ie \n(.g \{\
.ds `` \(lq
.ds '' \(rq
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.el \{\
.ie t .ds `` ``
.el   .ds `` ""
.ie t .ds '' ''
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.\}
.
.de bP
.ie n  .IP \(bu 4
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.ds d /etc/terminfo
.SH NAME
\fB\%tput\fP,
\fB\%init\fP,
\fB\%reset\fP \-
initialize a terminal, exercise its capabilities, or query \fI\%term\%info\fP database
.SH SYNOPSIS
\fBtput\fP [\fB\-T\fP \fIterminal-type\fP]
{\fIcap-code\fP [\fIparameter\fP .\|.\|.\&]} .\|.\|.
.PP
\fBtput\fP [\fB\-T\fP \fIterminal-type\fP] [\fB\-x\fP] \fBclear\fP
.PP
\fBtput\fP [\fB\-T\fP \fIterminal-type\fP] \fBinit\fP
.PP
\fBtput\fP [\fB\-T\fP \fIterminal-type\fP] \fB\%reset\fP
.PP
\fBtput\fP [\fB\-T\fP \fIterminal-type\fP] \fB\%longname\fP
.PP
\fBtput \-S\fP
.PP
\fBtput \-V\fP
.SH DESCRIPTION
\fB\%tput\fP uses the
.I \%term\%info
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
.IR cap-code .
.PP
\fB\%terminfo\fP(5) discusses terminal capabilities at length
and presents a complete list of
.I cap-codes.
.PP
When retrieving capability values,
the result depends upon the capability's type.
.TP 9 \" "Boolean" + 2n
Boolean
\fB\%tput\fP sets its exit status to
.B 0
if the terminal possesses
.I cap-code,
and
.B 1
if it does not.
.TP
numeric
\fB\%tput\fP writes
.IR cap-code 's
decimal value to the standard output stream if defined
.RB ( \-1
if it is not)
followed by a newline.
.TP
string
\fB\%tput\fP writes
.IR cap-code 's
value to the standard output stream if defined,
without a trailing newline.
.PP
Before using a value returned on the standard output,
the application should test \fB\%tput\fP's exit status
to be sure it is 0;
see section \*(``EXIT STATUS\*('' below.
.SS Operands
Generally,
an operand is a
.I cap-code,
a capability code from the terminal database,
or a parameter thereto.
Three others are specially recognized by \fB\%tput\fP:
.BR init ,
.BR \%reset ,
and
.BR \%longname .
Although these resemble capability codes,
they in fact receive special handling;
we term them \*(``pseudo-capabilities\*(''.
.TP 11n \" "longname" + 2n + adjustment for PDF
.I cap-code
indicates a capability from the terminal database.
.IP
If the capability is of string type and takes parameters,
the arguments following the capability will be used as its parameters.
.IP
Most parameters are numeric.
Only a few terminal capabilities require string parameters;
\fB\%tput\fP uses a table to decide which to pass as strings.
Normally \fB\%tput\fP uses \fB\%tparm\fP(3NCURSES) to perform the
substitution.
If no parameters are given for the capability,
\fB\%tput\fP writes the string without performing the substitution.
.TP
.B init
initializes the terminal.
If the terminal database is present
and an entry for the user's terminal type exists,
the following occur.
.RS
.TP 5
(1)
\fB\%tput\fP retrieves the terminal's mode settings.
It successively tests the file descriptors corresponding to
.RS
.bP
the standard error stream,
.bP
the standard output stream,
.bP
the standard input stream,
and
.bP
.I \%/dev/tty
.RE
.IP
to obtain terminal settings.
Having retrieved them,
\fB\%tput\fP remembers which descriptor to use for further updates.
.TP
(2)
If the terminal dimensions cannot be obtained from the operating system,
but the environment or terminal type database entry describes them,
\fB\%tput\fP updates the operating system's notion of them.
.TP
(3)
\fB\%tput\fP updates the terminal modes.
.RS
.bP
Any delays specified in the entry
(for example,
when a newline is sent)
are set in the terminal driver.
.bP
Tab expansion is turned on or off per the specification in the entry,
and
.bP
if tabs are not expanded,
standard tabs
(every 8 spaces)
are set.
.RE
.TP
(4)
If initialization capabilities,
detailed in subsection \*(``Tabs and Initialization\*('' of
\fB\%terminfo\fP(5),
are present,
\fB\%tput\fP writes them to the standard output stream.
.TP
(5)
\fB\%tput\fP flushes the standard output stream.
.RE
.IP
If an entry lacks the information needed for an activity above,
that activity is silently skipped.
.TP
.B reset
re-initializes the terminal.
A reset differs from initialization in two ways.
.RS
.TP 5
(1)
\fB\%tput\fP sets the the terminal modes to a \*(``sane\*('' state,
.RS
.bP
enabling cooked and echo modes,
.bP
disabling cbreak and raw modes,
.bP
enabling newline translation,
and
.bP
setting any unset special characters to their default values.
.RE
.TP 5
(2)
If any reset capabilities are defined for the terminal type,
\fB\%tput\fP writes them to the output stream.
Otherwise,
\fB\%tput\fP uses any defined initialization capabilities.
Reset capabilities are detailed in subsection
\*(``Tabs and Initialization\*('' of \fB\%terminfo\fP(5).
.RE
.TP
.B longname
A
.I \%term\%info
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.
.IP
\fB\%tic\fP warns if the last name does not include blanks,
to accommodate old
.I \%term\%info
entries that treated the long name as an optional feature.
The long name is often referred to as the description field.
.IP
If the terminal database is present and an entry for the user's terminal
type exists,
\fB\%tput\fP reports its description to the standard output stream,
without a trailing newline.
See \fB\%terminfo\fP(5).
.PP
.I Note:
Redirecting the output of
.RB \%\*(`` "tput init" \*(''
or
.RB \%\*(`` "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 \fB\%ioctl\fP(2).
.SS Aliases
If \fB\%tput\fP is invoked via link with any of the names
.BR clear ,
.BR init ,
or
.BR \%reset ,
it operates as if run with the corresponding (pseudo-)capability
operand.
For example,
executing a link named
.B \%reset
that points to \fB\%tput\fP has the same effect as
.RB \%\*(`` "tput \%reset" \*(''.
(The \fB\%tset\fP(1) utility also treats a link named
.B \%reset
specially.)
.PP
If \fB\%tput\fP is invoked by a link named
.BR \%init ,
this has the same effect as
.RB \%\*(`` "tput init" \*(''.
Such a link is seldom employed because another program of that name
is in widespread use.
.SS "Terminal Size"
Besides the pseudo-capabilities
(such as
.BR init ),
\fB\%tput\fP treats the
.B lines
and
.B cols
.I cap-codes
specially:
it may call \fB\%setupterm\fP(3NCURSES) to obtain the terminal size.
.bP
First,
\fB\%tput\fP 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.
.bP
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.
.bP
Finally,
it inspects the environment variables
.I LINES
and
.I \%COLUMNS,
which may override the terminal size.
.PP
If the
.B \-T
option is given,
\fB\%tput\fP ignores the environment variables by calling
.BR \%use_tioctl(TRUE) ,
relying upon the operating system
(or,
ultimately,
the terminal database).
.SH OPTIONS
.TP 9n \" "-T type" + 2n
.B \-S
retrieves more than one capability per invocation of \fB\%tput\fP.
The capabilities must be passed to \fB\%tput\fP from the standard
input stream instead of from the command line
(see section \*(``EXAMPLES\*('' below).
Only one
.I cap-code
is allowed per line.
The
.B \-S
option changes the meanings of the
.B 0
and
.B 1
exit statuses
(see section \*(``EXIT STATUS\*('' below).
.IP
Some capabilities use string parameters rather than numeric ones.
\fB\%tput\fP employs a built-in table and the presence of parameters
in its input to decide how to interpret them,
and whether to use \fB\%tparm\fP(3NCURSES).
.TP
.BI \-T\  type
indicates the terminal's
.I type.
Normally this option is unnecessary,
because a default is taken from the
.I TERM
environment variable.
If specified,
the environment variables
.I LINES
and
.I \%COLUMNS
are also ignored.
.TP
.B \-V
reports the version of
.I \%ncurses
associated with \fB\%tput\fP,
and exits with a successful status.
.TP
.B \-x
prevents
.RB \%\*(`` "tput clear" \*(''
from attempting to clear the scrollback buffer.
.SH EXIT STATUS
Normally,
one should interpret \fB\%tput\fP's exit statuses as follows.
.PP
.if n .ne 3
.if t .ne 2
.TS
Lb Lb
Lb Lx.
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 + \fBerrno\fP)
.TE
.PP
When the
.B \-S
option is used,
some statuses change meanings.
.PP
.if n .ne 4
.if t .ne 3
.TS
Lb Lb
Lb Lx.
Status	Meaning When \-S Specified
_
0	all operands interpreted
1	unused
4	some operands not interpreted
.TE
.SH ENVIRONMENT
\fBtput\fP command reads one environment variable.
.TP 8n \" "TERM" + 2n + adjustment for PDF
.I TERM
denotes the terminal type.
Each terminal type is distinct,
though many are similar.
The
.B \-T
option overrides its value.
.SH FILES
.TP
.I /usr/share/tabset
tab stop initialization database
.TP
.I \*d
compiled terminal description database
.SH PORTABILITY
Over time
.I \%ncurses
\fB\%tput\fP
has differed from that of System\ V in two important respects,
one now mostly historical.
.bP
\%\*(``\fBtput\fP
.IR 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.
.IP
System\ V
.BR tput 's
.B init
and
.B \%reset
operands use logic from 4.1cBSD
.BR tset ,
manipulating terminal modes.
It checks the same file descriptors
(and
.IR \%/dev/tty )
for association with a terminal device as
.I \%ncurses
now does,
and if none are,
finally assumes a 1200 baud terminal.
When updating terminal modes,
it ignores errors.
.IP
Until
.I \%ncurses
6.1
(see section \*(``HISTORY\*('' below),
\fB\%tput\fP did not modify terminal modes.
It now employs a scheme similar to System\ V,
using functions shared with \fB\%tset\fP
(and ultimately based on 4.4BSD
.BR tset ).
If it is not able to open a terminal
(for instance,
when run by \fIcron\fP(1)),
\fB\%tput\fP exits with an error status.
.bP
System\ V
.B tput
assumes that the type of a
.I cap-code
operand is numeric if all the characters of its value are decimal
numbers;
if they are not,
it treats
.I cap-code
as a string capability.
.IP
Most implementations that provide support for
.I cap-code
operands use the \fB\%tparm\fP(3NCURSES) function to expand its parameters.
That function expects a mixture of numeric and string parameters,
requiring \fB\%tput\fP to know which type to use.
.IP
.I \%ncurses
\fB\%tput\fP
uses a table to determine the parameter types for
the standard
.I cap-code
operands,
and an internal function to analyze nonstandard
.I cap-code
operands.
.IP
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
.I \%ncurses
to port NetBSD's
.IR termcap -based
.B tput
to
.I \%term\%info,
and modified it to interpret multiple
.I cap-codes
(and parameters)
on the command line.
Portable applications should not rely upon this feature;
.I \%ncurses
offers it to support applications written specifically for OpenBSD.
.PP
This implementation,
unlike others,
accepts both
.I termcap
and
.I \%term\%info
.I cap-codes
if
.I termcap
support is compiled in.
In that case,
however,
the predefined
.I termcap
and
.I \%term\%info
codes have two
ambiguities;
.I \%ncurses
assumes the
.I \%term\%info
code.
.bP
The
.I cap-code
.B dl
means
.B \%delete_line
to
.I termcap
but
.B \%parm_delete_line
to
.I \%term\%info.
.I termcap
uses the code
.B DL
for
.BR \%parm_delete_line .
.I \%term\%info
uses the code
.B dch1
for
.BR \%delete_line .
.bP
The
.I cap-code
.B ed
means
.B \%exit_delete_mode
to
.I termcap
but
.B \%clr_eos
to
.I \%term\%info.
.I termcap
uses the code
.B cd
for
.BR \%clr_eos .
.I \%term\%info
uses the code
.B rmdc
for
.BR \%exit_delete_mode .
.PP
The
.B \%longname
operand,
.B \-S
option,
and the parameter-substitution features used in the
.B cup
example below,
were not supported in
AT&T/USL
.I curses
before SVr4 (1989).
Later,
4.3BSD-Reno (1990) added support for
.BR \%longname ,
.\" longname was added in October 1989.
and in 1994,
NetBSD added support for the parameter-substitution features.
.PP
IEEE Std 1003.1/The Open Group Base Specifications Issue 7
(POSIX.1-2008)
documents only the
.BR clear ,
.BR init ,
and
.B \%reset
operands.
A few observations of interest arise from that selection.
.bP
.I \%ncurses
supports
.B clear
as it does any other standard
.I cap-code.
The others
.RB ( init
and
.BR \%longname )
do not correspond to terminal capabilities.
.bP
The
.B tput
on SVr4-based systems such as Solaris,
IRIX64,
and HP-UX,
as well as others such as AIX and Tru64,
also support standard
.I cap-code
operands.
.bP
A few platforms such as FreeBSD recognize
.I termcap
names rather than
.I \%term\%info
capability names in their respective
.B tput
commands.
Since 2010,
NetBSD's
.B tput
uses
.I \%term\%info
names.
Before that,
it
(like FreeBSD)
recognized
.I termcap
names.
.IP
Beginning in 2021,
FreeBSD uses
.I \%ncurses
.BR tput ,
configured for both
.I \%term\%info
(tested first)
and
.I termcap
(as a fallback).
.PP
Because (apparently) all
.I certified
Unix systems support the full set of capability codes,
the reason for documenting only a few may not be apparent.
.bP
X/Open Curses Issue 7 documents
.B tput
differently,
with
.I cap-code
and the other features used in this implementation.
.bP
That is,
there are two standards for
.BR 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.
.bP
While it is certainly possible to write a
.B tput
program without using
.I curses,
no system with a
.I curses
implementation provides a
.B tput
utility that does not also support standard
.I cap-codes.
.PP
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
.I curses
behavior).
.bP
It assigns exit status 4 to \*(``invalid operand\*('',
which may have the same meaning as \*(``unknown capability\*(''.
For instance,
the source code for
Solaris
.I xcurses
uses the term \*(``invalid\*('' in this case.
.bP
It assigns exit status 255 to a numeric variable that is not specified
in the
.I \%term\%info
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.
.PP
The various System\ V implementations
(AIX,
HP-UX,
Solaris)
use the same exit statuses as
.I \%ncurses.
.PP
NetBSD
.I curses
documents exit statuses that correspond to neither
.I \%ncurses
nor X/Open Curses.
.SH HISTORY
Bill Joy wrote a
.B tput
command during development of 4BSD in October 1980.
This initial version only cleared the screen,
and did not ship with official distributions.
.\" It also exited with backwards exit status (1 on success, 0 on
.\" failure), and was characterized by Bostic in 1988 as "pretty
.\" unreasonable".
.\" See Spinellis's "unix-history-repo" on GitHub.
.PP
System\ V developed a different
.B tput
command.
.bP
SVr2 (1984) provided a rudimentary
.B tput
that checked the parameter against each
predefined capability and returned the corresponding value.
This version of
.B tput
did not use \fB\%tparm\fP(3NCURSES) for parameterized capabilities.
.bP
SVr3 (1987) replaced that
.\" SVr3 released in 1987, not 1985.
.\" https://unix.org/what_is_unix/history_timeline.html
with a more extensive program
whose support for
.B init
and
.B \%reset
operands
(more than half the program)
incorporated the
.B \%reset
feature of BSD
.B tset
written by Eric Allman.
.bP
SVr4 (1989) added color initialization by using the
.B \%orig_colors
.RB ( oc )
and
.B \%orig_pair
.RB ( op )
capabilities in its
.B init
logic.
.PP
Keith Bostic refactored BSD
.B tput
for shipment in 4.3BSD-Tahoe (1988),
then replaced it the next year with a new implementation based on
System\ V
.BR tput .
Bostic's version similarly accepted some parameters named for
.I \%term\%info
(pseudo-)capabilities:
.BR clear ,
.BR init ,
.BR \%longname ,
and
.BR \%reset .
However,
because he had only
.I termcap
available,
it accepted
.I termcap
names for other capabilities.
Also,
Bostic's BSD
.B tput
did not modify the terminal modes as the earlier BSD
.B tset
had done.
.PP
At the same time,
Bostic added a shell script named \*(``clear\*('' that used
.B tput
to clear the screen.
Both of these appeared in 4.4BSD,
becoming the \*(``modern\*('' BSD implementation of
.BR tput .
.PP
The origin of
.I \%ncurses
\fB\%tput\fP lies outside both System\ V and BSD,
in Ross Ridge's
.I \%mytinfo
package,
published on
.I 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
.B tput
program
(and other parts of
.IR \%mytinfo )
in
.I \%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.
.PP
Before
.I \%ncurses
6.1 (2018),
its \fB\%tset\fP and \fB\%tput\fP utilities differed.
.bP
\fB\%tset\fP was more effective,
resetting the terminal modes and special characters.
.bP
On the other hand,
\fB\%tset\fP's repertoire of terminal capabilities for resetting the
terminal was more limited;
it had only equivalents of
.B \%reset_1string
.RB ( rs1 ),
.B \%reset_2string
.RB ( rs2 ),
and
.B \%reset_file
.RB ( rf ),
and not the tab stop and margin update features of \fB\%tput\fP.
.PP
The
.B \%reset
program is traditionally an alias for \fB\%tset\fP due to its ability
to reset terminal modes and special characters.
.PP
As of
.I \%ncurses
6.1,
the \*(``reset\*('' features of the two programs are (mostly) the same.
Two minor differences remain.
.bP
The \fB\%tset\fP program waits one second when resetting,
in case the terminal happens to be a hardware device.
.bP
The two programs write the terminal initialization strings
to different streams;
that is,
standard error for \fB\%tset\fP and
standard output for \fB\%tput\fP.
.SH EXAMPLES
.TP
.B "tput init"
Initialize the terminal according to the type of
terminal in the
.I TERM
environment variable.
If the system does not reliably initialize the terminal upon login,
this command can be included in
.I \%$HOME/.profile
after exporting the
.I TERM
environment variable.
.TP
.B "tput \-T5620 reset"
Reset an AT&T 5620 terminal,
overriding the terminal type in the
.I TERM
environment variable.
.TP
.B "tput cnorm"
Set cursor to normal visibility.
.TP
.B "tput home"
Move the cursor to row 0,
column 0:
the upper left corner of the screen,
usually known as the \*(``home\*('' cursor position.
.TP
.B "tput clear"
Clear the screen:
write the
.B \%clear_screen
capability's value to the standard output stream.
.TP
.B "tput cols"
Report the number of columns used by the current terminal type.
.TP
.B "tput \-Tadm3a cols"
Report the number of columns used by an ADM-3A terminal.
.TP
.B "strong=\(gatput smso\(ga normal=\(gatput rmso\(ga"
Set shell variables to capability values:
.B strong
and
.BR normal ,
to begin and end,
respectively,
stand-out mode for the terminal.
One might use these to present a prompt.
.IP
.EX
.RS 14
printf "${strong}Username:${normal} "
.RE
.EE
.TP
.B "tput hc"
Indicate via exit status whether the terminal is a hard copy device.
.TP
.B "tput cup 23 4"
Move the cursor to row 23,
column 4.
.TP
.B "tput cup"
Report the value of the
.B \%cursor_address
.RB ( cup )
capability
(used for cursor movement),
with no parameters substituted.
.TP
.B "tput longname"
Report the
.I \%term\%info
database's description of the terminal type specified in the
.I TERM
environment variable.
.TP
.B "tput \-S"
Process multiple capabilities.
The
.B \-S
option can be profitably used with a shell \*(``here document\*(''.
.IP
.EX
.RB $\  "tput \-S <<!"
.RB >\  clear
.RB >\  "cup 10 10"
.RB >\  bold
.RB >\  !
.EE
.IP
The foregoing
clears the screen,
moves the cursor to position
(10, 10)
and turns on bold
(extra bright)
mode.
.TP
.B "tput clear cup 10 10 bold"
Perform the same actions as the foregoing
.RB \%\*(`` "tput \-S" \*(''
example.
.SH SEE ALSO
\fB\%clear\fP(1),
\fB\%stty\fP(1),
\fB\%tabs\fP(1),
\fB\%tset\fP(1),
\fB\%termcap\fP(3NCURSES),
\fB\%terminfo\fP(5)