# tput

## 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.
    


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