Provided by: ncurses-bin_6.4+20240113-1ubuntu2_amd64 bug

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)