PROLOG

       This  manual  page  is part of the POSIX Programmer's Manual.  The Linux implementation of
       this interface may differ (consult the corresponding Linux  manual  page  for  details  of
       Linux behavior), or the interface may not be implemented on Linux.

NAME

       tput — change terminal characteristics

SYNOPSIS

       tput [-T type] operand...

DESCRIPTION

       The  tput  utility  shall display terminal-dependent information. The manner in which this
       information is retrieved  is  unspecified.  The  information  displayed  shall  clear  the
       terminal  screen,  initialize the user's terminal, or reset the user's terminal, depending
       on  the  operand  given.  The  exact  consequences  of  displaying  this  information  are
       unspecified.

OPTIONS

       The  tput  utility  shall  conform to the Base Definitions volume of POSIX.1‐2017, Section
       12.2, Utility Syntax Guidelines.

       The following option shall be supported:

       -T type   Indicate the type of terminal. If this option  is  not  supplied  and  the  TERM
                 variable  is  unset or null, an unspecified default terminal type shall be used.
                 The setting of type shall take precedence over the value in TERM.

OPERANDS

       The following strings shall be supported as operands by the implementation  in  the  POSIX
       locale:

       clear     Display the clear-screen sequence.

       init      Display  the sequence that initializes the user's terminal in an implementation-
                 defined manner.

       reset     Display the sequence that resets  the  user's  terminal  in  an  implementation-
                 defined manner.

       If  a  terminal  does  not support any of the operations described by these operands, this
       shall not be considered an error condition.

STDIN

       Not used.

INPUT FILES

       None.

ENVIRONMENT VARIABLES

       The following environment variables shall affect the execution of tput:

       LANG      Provide a default value for the internationalization variables that are unset or
                 null.   (See   the   Base  Definitions  volume  of  POSIX.1‐2017,  Section  8.2,
                 Internationalization  Variables  for  the  precedence  of   internationalization
                 variables used to determine the values of locale categories.)

       LC_ALL    If  set  to  a  non-empty  string  value,  override  the values of all the other
                 internationalization variables.

       LC_CTYPE  Determine the locale for the interpretation of sequences of bytes of  text  data
                 as  characters  (for example, single-byte as opposed to multi-byte characters in
                 arguments).

       LC_MESSAGES
                 Determine the locale that should be used to affect the format  and  contents  of
                 diagnostic messages written to standard error.

       NLSPATH   Determine the location of message catalogs for the processing of LC_MESSAGES.

       TERM      Determine  the  terminal  type. If this variable is unset or null, and if the -T
                 option is not specified, an unspecified default terminal type shall be used.

ASYNCHRONOUS EVENTS

       Default.

STDOUT

       If standard output is a terminal device, it  may  be  used  for  writing  the  appropriate
       sequence  to  clear  the screen or reset or initialize the terminal. If standard output is
       not a terminal device, undefined results occur.

STDERR

       The standard error shall be used only for diagnostic messages.

OUTPUT FILES

       None.

EXTENDED DESCRIPTION

       None.

EXIT STATUS

       The following exit values shall be returned:

        0    The requested string was written successfully.

        1    Unspecified.

        2    Usage error.

        3    No information is available about the specified terminal type.

        4    The specified operand is invalid.

       >4    An error occurred.

CONSEQUENCES OF ERRORS

       If one of the operands is not available for the terminal, tput  continues  processing  the
       remaining operands.

       The following sections are informative.

APPLICATION USAGE

       The  difference between resetting and initializing a terminal is left unspecified, as they
       vary greatly based on hardware types. In general, resetting is a more severe action.

       Some terminals use control characters  to  perform  the  stated  functions,  and  on  such
       terminals it might make sense to use tput to store the initialization strings in a file or
       environment variable for later use. However, because other terminals might rely on  system
       calls  to  do  this work, the standard output cannot be used in a portable manner, such as
       the following non-portable constructs:

           ClearVar=`tput clear`
           tput reset | mailx -s "Wake Up" ddg

EXAMPLES

        1. Initialize the terminal according  to  the  type  of  terminal  in  the  environmental
           variable TERM.  This command can be included in a .profile file.

               tput init

        2. Reset a 450 terminal.

               tput -T 450 reset

RATIONALE

       The list of operands was reduced to a minimum for the following reasons:

        *  The  only  features  chosen  were  those  that  were  likely to be used by human users
           interacting with a terminal.

        *  Specifying the full terminfo set  was  not  considered  desirable,  but  the  standard
           developers did not want to select among operands.

        *  This   volume   of   POSIX.1‐2017  does  not  attempt  to  provide  applications  with
           sophisticated terminal handling capabilities, as that falls outside  of  its  assigned
           scope and intersects with the responsibilities of other standards bodies.

       The  difference  between resetting and initializing a terminal is left unspecified as this
       varies greatly based on hardware types. In general, resetting is a more severe action.

       The exit status of 1 is historically reserved for finding out if a Boolean operand is  not
       set. Although the operands were reduced to a minimum, the exit status of 1 should still be
       reserved for the Boolean operands, for those sites that wish to support them.

FUTURE DIRECTIONS

       None.

SEE ALSO

       stty, tabs

       The Base Definitions volume of POSIX.1‐2017, Chapter  8,  Environment  Variables,  Section
       12.2, Utility Syntax Guidelines

COPYRIGHT

       Portions  of  this  text  are  reprinted  and  reproduced in electronic form from IEEE Std
       1003.1-2017, Standard for Information Technology -- Portable  Operating  System  Interface
       (POSIX),  The  Open Group Base Specifications Issue 7, 2018 Edition, Copyright (C) 2018 by
       the Institute of Electrical and Electronics Engineers, Inc and The  Open  Group.   In  the
       event  of  any  discrepancy  between this version and the original IEEE and The Open Group
       Standard, the original IEEE and The Open Group  Standard  is  the  referee  document.  The
       original Standard can be obtained online at http://www.opengroup.org/unix/online.html .

       Any  typographical  or  formatting errors that appear in this page are most likely to have
       been introduced during the conversion of the source files to man page  format.  To  report
       such errors, see https://www.kernel.org/doc/man-pages/reporting_bugs.html .