# clear 1

    clear(1)                    General Commands Manual                   clear(1)

## NAME

           clear - clear the terminal screen

## SYNOPSIS

           clear [-Ttype] [-V] [-x]

## DESCRIPTION

           clear  clears your screen if this is possible, including its scrollback
           buffer (if the extended "E3" capability is defined).   clear  looks  in
           the environment for the terminal type given by the environment variable
           TERM, and then in the terminfo database to determine how to  clear  the
           screen.

           clear  writes  to  the  standard output.  You can redirect the standard
           output to a file (which  prevents  clear  from  actually  clearing  the
           screen),  and  later  cat  the  file to the screen, clearing it at that
           point.

## OPTIONS

           -T type
                indicates  the  type  of  terminal.   Normally  this   option   is
                unnecessary,  because  the  default  is taken from the environment
                variable TERM.  If -T is specified, then the shell variables LINES
                and COLUMNS will also be ignored.

           -V   reports the version of ncurses which was used in this program, and
                exits.  The options are as follows:

           -x   do not attempt to clear the terminal's scrollback buffer using the
                extended "E3" capability.

## HISTORY

           A  clear  command  appeared  in 2.79BSD dated February 24, 1979.  Later
           that was provided in Unix 8th edition (1985).

           AT&T adapted a different BSD program  (tset)  to  make  a  new  command
           (tput),  and used this to replace the clear command with a shell script
           which calls tput clear, e.g.,

               /usr/bin/tput ${1:+-T$1} clear 2> /dev/null
               exit

           In 1989, when Keith Bostic revised the BSD  tput  command  to  make  it
           similar  to  the  AT&T  tput,  he  added  a  shell script for the clear
           command:

               exec tput clear

           The remainder of the script in each case is a copyright notice.

           The ncurses clear command began in 1995 by adapting  the  original  BSD
           clear command (with terminfo, of course).

           The E3 extension came later:

           o   In  June  1999, xterm provided an extension to the standard control
               sequence for clearing the screen.  Rather than  clearing  just  the
               visible part of the screen using

                   printf '\033[2J'

               one could clear the scrollback using

                   printf '\033[3J'

               This  is  documented  in  XTerm  Control  Sequences  as  a  feature
               originating with xterm.

           o   A few other terminal developers adopted the feature, e.g., PuTTY in
               2006.

           o   In  April  2011, a Red Hat developer submitted a patch to the Linux
               kernel, modifying its console driver to do  the  same  thing.   The
               Linux  change,  part  of  the  3.0  release, did not mention xterm,
               although it was cited in the Red Hat bug report (#683733) which led
               to the change.

           o   Again,  a  few  other terminal developers adopted the feature.  But
               the next relevant step was a change to the clear program in 2013 to
               incorporate this extension.

           o   In  2013,  the E3 extension was overlooked in tput with the "clear"
               parameter.  That was addressed in  2016  by  reorganizing  tput  to
               share its logic with clear and tset.

## PORTABILITY

           Neither IEEE Std 1003.1/The Open  Group  Base  Specifications  Issue  7
           (POSIX.1-2008) nor X/Open Curses Issue 7 documents tset or reset.

           The latter documents tput, which could be used to replace this  utility
           either  via  a shell script or by an alias (such as a symbolic link) to
           run tput as clear.

## SEE ALSO

           tput(1), terminfo(5)

           This describes ncurses version 6.2 (patch 20211009).

                                                                          clear(1)