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 .

IEEE/The Open Group                                   2017                                          TPUT(1POSIX)